Scenic views are offered on both the Maryland side and the Virginia side, the Billy Goat Trail on Bear Island, accessible from Maryland, offers scenic views of the Great Falls, as do vantage points on Olmsted Island (also accessible from Maryland). There are overlook points on the Virginia side.

Contents

This section needs expansion. You can help by adding to it.(August 2010)

Roughly 35,000 years ago, the Potomac River began carving out the Great Falls of the Potomac, the river cascades over a series of 20-foot (6.1 m) falls, falling a total of 76 feet (23 m) in elevation over a distance of less than 1 mile (1.6 km).[1]

The Potomac narrows significantly as it passes over the falls and through Mather Gorge. Heavy rain or snow in the watershed upstream causes white-water floods which entirely submerge the rocks and even threaten the adjacent park visitor center (built on stilts for this reason). A pillar at the Virginia overlook, well above the river, marks the level of the 1936 Potomac Flood.

Remains of the feeder dam, for the Chesapeake and Ohio Canal, at Great Falls

Various attempts to build canals around Great Falls were undertaken, the remains of the Patowmack Canal on the Virginia side, were an early attempt to skirt the falls, using 5 locks. That canal was started by George Washington. Later the Chesapeake and Ohio Canal was built on the Maryland side of the falls, and ultimately connected the Potomac tidewater with Cumberland, Maryland, the Chesapeake and Ohio also used the Great Falls as a feeder (now abandoned) to supply water for its own use.

Montgomery County, Maryland
–
Montgomery County, officially the County of Montgomery, is a county in the U. S. state of Maryland. As of the 2010 census, the population was 971,777 and it is the most populous county in Maryland. The county seat and largest municipality is Rockville, although the place of Germantown is the most populous place. Montgomery County is included in the

4.
The former Montgomery County Courthouse in Rockville, Maryland, in January 2006, which served as the county courthouse from 1931 to 1982. The building now houses a state district court after the county court was moved to the Montgomery County Judicial Center.

Maryland
–
The states largest city is Baltimore, and its capital is Annapolis. Among its occasional nicknames are Old Line State, the Free State, the state is named after Henrietta Maria of France, the wife of Charles I of England. George Calvert was the first Lord of Baltimore and the first English proprietor of the colonial grant. Maryland was the state to

3.
Dramatic example of Maryland's fall line, a change in rock type and elevation that creates waterfalls in many areas along the Southwest to Northeast geological boundary that crosses the state. Great Falls, cliffs and rapids.

Fairfax County, Virginia
–
Fairfax County, officially the County of Fairfax, is a county in the Commonwealth of Virginia. As of the 2010 census, the population was 1,081,726, in 2015, it was estimated at 1,142,234, making it the Commonwealths most populous jurisdiction, with 13. 6% of Virginias population. The county seat is the City of Fairfax, though because it is an indep

1.
The Old Fairfax County Courthouse located in Fairfax City (photo from late 2010)

4.
Fairfax County is, along with Washington, a "core" employment jurisdiction of the Washington Metropolitan Area as indicated by this map. A U.S. Department of Labor study published in 2007 described Fairfax County as the second "economic pillar" of the Washington-area economy, along with the District of Columbia. The county has been described in Time as "one of the great economic success stories of our time."

Waterfall
–
A waterfall is a place where water flows over a vertical drop or a series of drops in the course of a stream or river. Waterfalls also occur where meltwater drops over the edge of an iceberg or ice shelf. Waterfalls are commonly formed in the course of a river. At these times the channel is narrow and deep. When the river courses over resistant bed

Potomac River
–
The Potomac River /pəˈtoʊmək/ is located along the mid-Atlantic Ocean coast of the United States and flows into the Chesapeake Bay. The river is approximately 405 miles long, with an area of about 14,700 square miles. In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States, over 5 millio

4.
The Potomac River flowing through water gaps in the Blue Ridge Mountains near Harpers Ferry, West Virginia. Virginia is on the left, Maryland on the right, West Virginia in the upper right.

Washington, D.C.
–
Washington, D. C. formally the District of Columbia and commonly referred to as Washington, the District, or simply D. C. is the capital of the United States. The signing of the Residence Act on July 16,1790, Constitution provided for a federal district under the exclusive jurisdiction of the Congress and the District is therefore not a part of any

Great Falls Park
–
Great Falls Park is a small National Park Service site in Virginia, United States. Situated on 800 acres along the banks of the Potomac River in northern Fairfax County, native American petroglyphs have been discovered within the park on cliffs overlooking Difficult Run. The park visitor center has the bottom portions of two wooden canal lock gates

1.
Great Falls Park

2.
Great Falls (climbing area)

3.
Panoramic view of Great Falls of the Potomac River

4.
Great Falls Park in the early 1900s

National Park Service
–
It was created on August 25,1916, by Congress through the National Park Service Organic Act and is an agency of the United States Department of the Interior. As of 2014, the NPS employs 21,651 employees who oversee 417 units, the National Park Service celebrated its centennial in 2016. National parks and national monuments in the United States were

1.
In 1916, a portfolio of nine major parks was published to generate interest. Printed on each brochure was a map showing the parks and principal railroad connections.

2.
National Park Service Arrowhead

3.
In 1934, a series of ten postage stamps were issued to commemorate the reorganization and expansion of the National Park Service.

Chesapeake and Ohio Canal
–
The canals principal cargo was coal from the Allegheny Mountains. Construction on the 184. 5-mile canal began in 1828 and ended in 1850 with the completion of a 50-mile stretch to Cumberland, a planned section to the Ohio River at Pittsburgh was never built. The canal way is now maintained as the Chesapeake and Ohio Canal National Historical Park,

Billy Goat Trail
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Section A of the trail, by far the most popular, is on Bear Island and traverses rough and rocky terrain, including a steep climb along a cliff face along the Potomac Rivers Mather Gorge. At another point in the trail, hikers are required to scramble over, sections B and C are less strenuous, section B requires only one brief scramble, and section

Olmsted Island
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It is a part of Potomac, Maryland. Named for Frederick Law Olmsted, Jr, the island is very rocky and has steep cliffs that face the river, where it has been eroded over time. It also has trees and vegetation, one might also spy a heron, small lizard or wild goose here. The total area of the island is no more than 0.2 square kilometers, a fenced-in

Kayaking
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Kayaking is the use of a kayak for moving across water. It is distinguished from canoeing by the position of the paddler. A kayak is a low-to-the-water, canoe-like boat in which the paddler sits facing forward, legs in front, using a paddle to pull front-to-back on one side. Most kayaks have closed decks, although sit-on-top and inflatable kayaks a

Whitewater rafting
–
Rafting and white water rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water, dealing with risk and the need for teamwork is often a part of the experience. It is considered a sport, and can be fatal. The Internationa

Rock climbing
–
Rock climbing is an activity in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a usually pre-defined route without falling. Due to the length and extended endurance required and because accidents are likely to happen on descent than asce

Hiking
–
Hiking is the preferred term, in Canada and the United States, for a long, vigorous walk, usually on trails, in the countryside, while the word walking is used for shorter, particularly urban walks. On the other hand, in the United Kingdom, and the Republic of Ireland, the word hiking is also often used in the UK, along with rambling, hillwalking,

Mather Gorge
–
Mather Gorge is a river gorge south and just downriver of Great Falls in the state of Maryland bordering Virginia. The Maryland land side of the gorge is Bear Island, part of the Chesapeake and Ohio Canal National Historical Park, both parks are National Park Service sites. The gorge is named after Stephen Mather, the first director of the National

1.
Mather Gorge from the Virginia side. The Potomac River lies fully within Maryland.

2.
Students scrambling over boulders on the Billy Goat Trail. Mather Gorge is on the left.

Metamorphic rock
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Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. The original rock is subjected to heat and pressure, causing profound physical and/or chemical change, the protolith may be a sedimentary, an igneous, or even an existing type of metamorphic rock. Metamorphic rocks m

Schist
–
Schist is a medium-grade metamorphic rock with medium to large, flat, sheet-like grains in a preferred orientation. It is defined by having more than 50% platy and elongated minerals, often finely interleaved with quartz and these lamellar minerals include micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out gra

2.
Microscopic view of garnet-mica-schist in thin section under polarized light with a large garnet crystal (black) in a matrix of quartz and feldspar (white and gray grains) and parallel strands of mica (red, purple and brown).

Patowmack Canal
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Few ventures were dearer to George Washington than his plan to make the Potomac River navigable as far as the Ohio River Valley. The way, Washington wrote, is easy and dictated by our clearest interest and it is to open a wide door, and make a smooth way for the produce of that Country to pass to our Markets. As a waterway west, the Potomac River c

1.
Lock 1 of the Patowmack Canal. Rounded pebbles and sand fill lock for stabilization. The lock is a total of 18 feet (5 m) deep.

2.
The Little Falls canal was reused for the Chesapeake and Ohio Canal. Here is part of it.

3.
Lock 2 of the Patowmack Canal

4.
Remains of House Falls / Long Canal / C&O Canal

George Washington
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George Washington was an American politician and soldier who served as the first President of the United States from 1789 to 1797 and was one of the Founding Fathers of the United States. He served as Commander-in-Chief of the Continental Army during the American Revolutionary War and he is popularly considered the driving force behind the nations

Cumberland, Maryland
–
Cumberland, officially the City of Cumberland, is a western gateway city and seat of Allegany County, Maryland, and the primary city of the Cumberland, MD-WV Metropolitan Statistical Area. At the 2010 census, the city had a population of 20,859, Cumberland is a regional business and commercial center for Western Maryland and the Potomac Highlands o

1.
Downtown Cumberland in July 2001

2.
Seal

3.
map of Braddock's Military Road

4.
Terminus of the Chesapeake and Ohio Canal in Cumberland. Highway bridge is Interstate 68. Canal place museum is the brick building behind bridge.

Chesapeake and Ohio Canal National Historical Park
–
The Chesapeake and Ohio Canal National Historical Park is a United States National Historical Park located in the District of Columbia and the states of Maryland and West Virginia. The park was established in 1961 as a National Monument by President Dwight D. Eisenhower to preserve the remains of the Chesapeake and Ohio Canal. The canal and towpath

1.
Chesapeake and Ohio Canal National Historical Park

2.
The Cumberland basin at the canal's terminus in 2013. This area has been changed drastically and is almost unrecognizable compared to how it was during the canal's operating days

3.
Park map

4.
Work on restoring Lock 16 on the canal in 1939.

NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration effor

1.
1963 photo showing Dr. William H. Pickering, (center) JPL Director, President John F. Kennedy, (right). NASA Administrator James Webb in background. They are discussing the Mariner program, with a model presented.

Pennsylvania
–
Pennsylvania /ˌpɛnsᵻlˈveɪnjə/, officially the Commonwealth of Pennsylvania, is a state located in the northeastern and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle, Pennsylvania is the 33rd largest, the 5th most populous, and the 9th most densely populated of the 50 United States. The states five most

West Virginia
–
West Virginia /ˌwɛst vərˈdʒɪnjə/ is a state located in the Appalachian region of the Southern United States. It is bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the north, West Virginia is the 9th smallest by area, is ranked 38th in population, and has the second lowest household income of

4.
On October 24, 1861, when voters from 41 counties voted to form a new state, voter turnout was 34%. The name was subsequently changed from Kanawha to West Virginia.

Gulf Branch

1.
Gulf Branch

Donaldson Run
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Donaldson Run is a stream in Arlington County, Virginia. From its source near Marymount University, Donaldson Run flows on a northeastern course, Donaldson Run is surrounded predominantly by forests. Donaldson Run was named after Robert H. Donaldson, one of the farm owners. The land was settled by James Donaldson, then inherited by James son, Willi

1.
Donaldson Run

Windy Run

1.
Windy Run near its confluence with the Potomac

Rock Creek (Potomac River)
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Rock Creek is a free-flowing tributary of the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The creek is 32.6 miles long, with an area of about 76.5 square miles. The last quarter-mile of the creek is affected by tides, the creek rises from a spring near Laytonsville in Montgomery County, in the U. S. state of Marylan

Piney Branch
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Piney Branch is a tributary of Rock Creek in Washington, D. C. It is the largest tributary located entirely within the Washington city limits, Rock Creek drains to the Potomac River, which empties into the Chesapeake Bay. Piney Branch is a first order stream with a length of 0.75 miles. It is generally about 12 feet wide and 4 inches deep and it is

Boundary Channel
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Boundary Channel is a channel off the Potomac River in Washington, D. C. The channel begins at the tip of Columbia Island extends southward between Columbia Island and the Virginia shoreline. It curves around the tip of Columbia Island before heading northeast to exit into the Potomac River. At the southwestern tip of Columbia Island, the Boundary

1.
Map of area surrounding Boundary Channel and the Pentagon Lagoon

2.
Aerial view of the Columbia Island Marina and the Pentagon Lagoon in relationship to The Pentagon and the Potomac River.

3.
Corona image of The Pentagon and part of the Lagoon, 25 September 1967

Tiber Creek
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Tiber Creek or Tyber Creek is a tributary of the Potomac River in Washington, D. C. In the 19th century it was modified to become part of the Washington City Canal, originally called Goose Creek, it was renamed by settler Francis Pope. It was southeast of then Georgetown, Maryland, amid lands that were selected for the City of Washington and it flo

1.
Tiber/Goose Creek around 1800, and the modern shorelines of the Potomac River.

Washington Channel
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The Washington Channel is a channel that parallels the Potomac River in Washington, D. C. It is located between the Southwest Waterfront on the east side and East Potomac Park on the west side, the channel is two miles long, receives outflow from the Tidal Basin at its north end, and empties into the Anacostia River at Hains Point at its south end.

2.
Aerial view from the south of East Potomac Park and the Washington Channel, ca. 1935.

Anacostia River
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The Anacostia River /ænəˈkɒstiə/ is a river in the Mid Atlantic region of the United States. It flows from Prince Georges County in Maryland into Washington, D. C. where it joins with the Washington Channel to empty into the Potomac River at Buzzard Point and it is approximately 8.7 miles long. The name Anacostia derives from the early history as N

3.
Aerial view of Southeast DC in 2009 showing the progress of the Anacostia River

Northwest Branch Anacostia River
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Northwest Branch Anacostia River is a 21. 5-mile-long free-flowing stream in Montgomery County and Prince Georges County, Maryland. It is a tributary of the Anacostia River, which flows to the Potomac River, the headwaters of the Northwest Branch are located near the community of Sandy Spring. The stream flows southward for 21.5 miles to its conflu

1.
Map of the Anacostia River watershed showing the Northwest Branch

Sligo Creek
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Sligo Creek is a free-flowing tributary of the Northwest Branch of the Anacostia River in Maryland. The creek is approximately 9.1 miles long, with an area of about 11.6 square miles. It also inspired Katherine Paterson to write the Newbery Medal award winning book Bridge to Terabithia, the creek rises in the Kemp Mill section of Silver Spring in M

1.
The creek running through Silver Spring, Maryland

Northeast Branch Anacostia River
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Northeast Branch Anacostia River is a 3. 2-mile-long free-flowing stream in Prince Georges County, Maryland. It is a tributary of the Anacostia River, which flows to the Potomac River, the headwaters of the Northeast Branch are at the confluence of Indian Creek and Paint Branch, located on the eastern edge of the community of College Park. The stre

Four Mile Run
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Most of the stretch is parkland and is paralleled by two paved non-motorized transport and recreational trails, the Washington & Old Dominion Railroad Trail and the Four Mile Run Trail. In Arlington, the passes from the Piedmont through the fall line to the Atlantic Coastal Plain in a deep forested valley. The streams eastern section forms the boun

1.
Four Mile Run near Arlington's Jennie Dean Park

2.
Carlin Springs Historical Marker

Oxon Creek
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Oxon Creek is a cove on the Potomac River which straddles the border between Washington, D. C. and Prince Georges County, Maryland just north of Interstate 495 at Woodrow Wilson Bridge. The tributary stream is Oxon Run, Oxon Creek is 1.5 miles in length and empties into the Potomac at Goose Island across from the city of Alexandria, Virginia. To th

1.
Anacostia Freeway Crossing Oxon Creek to join the Beltway (2007) - Wilson Bridge is to the left

Hunting Creek
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Hunting Creek is a cove and tributary stream of the Potomac River between the City of Alexandria and Fairfax County in Virginia. It is formed by the confluence of Cameron Run and Hooff Run, the community of Huntington takes its name from the creek. Jones Point forms the north side, dyke Marsh is just to the south. The George Washington Memorial Par

1.
Hunting Creek seen from the east in 2010; Alexandria is to the right

2.
Hunting Creek from the west in 2015

Cameron Run
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Cameron Run is a 3. 0-mile-long tributary stream of the Potomac River, located in the U. S. state of Virginia. A third-order stream, it is formed by the confluence of Backlick Run and it flows eastward from Alexandria and forms the border between Fairfax County and Alexandria before opening into Hunting Creek and then into the Potomac River. Camero

Piscataway Creek
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Piscataway Creek is an 18. 6-mile-long tributary of the Potomac River in Prince Georges County, Maryland. The creek is an arm of the Potomac for its final 2.5 miles. Tinkers Creek is a tributary to Piscataway Creek, converging from the north 4.5 miles upstream of the mouth of the Piscataway, the United States Geological Survey records two variant n

1.
Mouth of Piscataway Creek, as seen from across the Potomac River

Little Hunting Creek
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Little Hunting Creek is a 3. 6-mile-long primarily tidal tributary of the Potomac River located in Fairfax County, Virginia, not to be confused with Hunting Creek farther north. The creek marks the location along the Potomac River where the Washington family built their Mount Vernon plantation during colonial times, the creek is bordered by residen

1.
Little Hunting Creek, viewed from its east bank looking south

2.
Colonial-era map of George Washington's estates surrounding Little Hunting Creek, including the Mount Vernon manor. The South Branch and part of the North Branch of the creek are visible.

Pohick Creek
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Pohick Creek is a 14. 0-mile-long tributary stream of the Potomac River in Fairfax County in the U. S. state of Virginia. It takes its name from the Pohick Native American tribe once prevalent in the area. Pohick Creek is a stream for whitewater kayaking, rafting. Several tributaries of the Pohick Creek are impounded by dams constructed under the W

Occoquan River
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The Occoquan River is a tributary of the Potomac River in Northern Virginia, where it serves as part of the boundary between Fairfax and Prince William counties. The river is 24.7 miles long, and its watershed covers about 590 square miles and it reaches the Potomac at Belmont Bay. The Occoquan River is part of the Chesapeake Bay watershed, the nam

1.
Occoquan River near Fountainhead Regional Park

Bull Run (Occoquan River)

Mattawoman Creek
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Mattawoman Creek is a 30. 0-mile-long coastal-plain tributary to the tidal Potomac River with a mouth at Indian Head, Maryland,20 miles downstream of Washington, D. C. It comprises a 23-mile river flowing through Prince Georges and Charles counties, about three-fourths of its 94-square-mile watershed lies in Charles County, with the remainder in Pr

1.
Freshwater-tidal estuary of Mattawoman Creek

Quantico Creek
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Quantico Creek is a 13. 7-mile-long tidal tributary of the Potomac River in eastern Prince William County, Virginia. Quantico Creek rises southeast of Independent Hill, flows through Prince William Forest Park, john Smith in 1608 reported the existence of a Doeg community called Pamacocack on the banks of this creek, as well as on the directly oppo

1.
Aquia Creek Landing in Union control in February 1863. This position swapped hands between the two armies during 1861 and 1862, until the Union established a logistical supply point here for the Army of the Potomac.

Potomac Creek

1.
Accokeek Creek entering Potomac Creek; Potomac River in background

Wicomico River (Potomac River)

1.
Cobb Island, MD is at the junction of Neale Sound, Wicomico River, and the Potomac River

Popes Creek (Virginia)

1.
The waters of Pope's Creek from across the cove showing the 20th century Memorial House

1.
On July 2, 1863, "Wiedrich's battery [of] six rifled cannon also exchanged fire with one of Jones's batteries on the opposite side of Rock Creek", [9] and snipers from a home on the East side fired on positions on the West side of the creek (on July 3, Confederates retreated across Rock Creek.) [10]

LIST OF IMAGES

1.
Montgomery County, Maryland
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Montgomery County, officially the County of Montgomery, is a county in the U. S. state of Maryland. As of the 2010 census, the population was 971,777 and it is the most populous county in Maryland. The county seat and largest municipality is Rockville, although the place of Germantown is the most populous place. Montgomery County is included in the Washington–Arlington–Alexandria, DC–VA–MD–WV Metropolitan Statistical Area, as one of the most affluent counties in the United States, it also has the highest percentage of residents over 25 years of age who hold post-graduate degrees. In 2011, it was ranked by Forbes as the 10th richest in the United States, the Maryland state legislature named Montgomery County after Richard Montgomery, the county was created from lands that had at one point or another been part of Frederick County. The name use of Montgomery and Washington County were seen as further defiance to Great Britain during the American Revolutionary War, the countys nickname of MoCo is derived from Montgomery County, after the pattern of SoHo, Manhattan. The countys motto, adopted in 1976, is Gardez Bien, the countys motto is also the motto of its namesakes family. Before European immigration, the now known as Montgomery County was covered in a vast swath of forest crossed by the creeks and small streams that feed the Potomac. A few small villages of the Piscataway, members of the Algonquian people, were scattered across the southern portions of the county. Captain John Smith of the English settlement at Jamestown was probably the first European to explore the area, during his travels along the Potomac River and throughout the Chesapeake region. These lands were claimed by Europeans for the first time when George Calvert and he and other early claimants had no intention of settling their families. They were little more than speculators, securing grants from the colonial leadership, thus, it was not until approximately 1715 that the first British settlers began building farms and plantations in the area. Most of these settlers were small farmers, growing wheat. Many of the farmers owned slaves and they transported the tobacco they grew to market through the Potomac River port of Georgetown. Sparsely settled, the farms and taverns were nonetheless of strategic importance as access to the interior. General Edward Braddocks army traveled through the county on the way to its disastrous defeat at Fort Duquesne during the French, like other regions of the American colonies, the region that is now Montgomery County saw protests against British taxation in the years before the American Revolution. In 1774, local residents met at Hungerfords Tavern and agreed to break off commerce with Great Britain, following the signing of the Declaration of Independence, representatives of the area helped to draft the new state constitution and began to build a Maryland free of proprietary control. The leaders of the new county chose as their county seat an area adjacent to Hungerfords Tavern near the center of the county, the newly formed Montgomery County supplied arms, food and forage for the Continental Army during the Revolution, in addition to soldiers

Montgomery County, Maryland
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Downtown Rockville in 2001, the Black Rock Mill in 2006, the National Naval Medical Center in 2003, Shady Grove in 2004, and the Gaithersburg city hall in 2007.
Montgomery County, Maryland
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Map of Montgomery County, Maryland. Compiled in the Bureau of Topographical Engineers from the latest and best authorities, September 1862.
Montgomery County, Maryland
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The Madison House in Brookeville was built around 1800 and originally owned by Caleb Bentley. The house provided refuge for President James Madison, on August 26, 1814, after the British burned Washington, D.C., during the War of 1812.
Montgomery County, Maryland
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The former Montgomery County Courthouse in Rockville, Maryland, in January 2006, which served as the county courthouse from 1931 to 1982. The building now houses a state district court after the county court was moved to the Montgomery County Judicial Center.

2.
Maryland
–
The states largest city is Baltimore, and its capital is Annapolis. Among its occasional nicknames are Old Line State, the Free State, the state is named after Henrietta Maria of France, the wife of Charles I of England. George Calvert was the first Lord of Baltimore and the first English proprietor of the colonial grant. Maryland was the state to ratify the United States Constitution. Maryland is one of the smallest U. S. states in terms of area, as well as one of the most densely populated, Maryland has an area of 12,406.68 square miles and is comparable in overall area with Belgium. It is the 42nd largest and 9th smallest state and is closest in size to the state of Hawaii, the next largest state, its neighbor West Virginia, is almost twice the size of Maryland. Maryland possesses a variety of topography within its borders, contributing to its nickname America in Miniature. The mid-portion of this border is interrupted by Washington, D. C. which sits on land that was part of Montgomery and Prince Georges counties and including the town of Georgetown. This land was ceded to the United States Federal Government in 1790 to form the District of Columbia, the Chesapeake Bay nearly bisects the state and the counties east of the bay are known collectively as the Eastern Shore. Close to the town of Hancock, in western Maryland, about two-thirds of the way across the state. This geographical curiosity makes Maryland the narrowest state, bordered by the Mason–Dixon line to the north, portions of Maryland are included in various official and unofficial geographic regions. Much of the Baltimore–Washington corridor lies just south of the Piedmont in the Coastal Plain, earthquakes in Maryland are infrequent and small due to the states distance from seismic/earthquake zones. The M5.8 Virginia earthquake in 2011 was felt moderately throughout Maryland, buildings in the state are not well-designed for earthquakes and can suffer damage easily. The lack of any glacial history accounts for the scarcity of Marylands natural lakes, laurel Oxbow Lake is an over one-hundred-year-old 55-acre natural lake two miles north of Maryland City and adjacent to Russett. Chews Lake is a natural lake two miles south-southeast of Upper Marlboro. There are numerous lakes, the largest of them being the Deep Creek Lake. Maryland has shale formations containing natural gas, where fracking is theoretically possible, as is typical of states on the East Coast, Marylands plant life is abundant and healthy. Middle Atlantic coastal forests, typical of the southeastern Atlantic coastal plain, grow around Chesapeake Bay, moving west, a mixture of Northeastern coastal forests and Southeastern mixed forests cover the central part of the state

3.
Fairfax County, Virginia
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Fairfax County, officially the County of Fairfax, is a county in the Commonwealth of Virginia. As of the 2010 census, the population was 1,081,726, in 2015, it was estimated at 1,142,234, making it the Commonwealths most populous jurisdiction, with 13. 6% of Virginias population. The county seat is the City of Fairfax, though because it is an independent city under Virginia law, the county is also home to seven Fortune 500 companies, including three with Falls Church addresses. At the time of European encounter, the inhabitants of what would become Fairfax County were an Algonquian-speaking sub-group called the Taux, also known as the Doeg or Dogue. Their villages, as recorded by Captain John Smith in 1608, included Namassingakent, virginian colonists from the Northern Neck region drove the Doeg out of this area and into Maryland by 1670. Fairfax County was formed in 1742 from the part of Prince William County. It was named for Thomas Fairfax, 6th Lord Fairfax of Cameron, the Fairfax family name is derived from the Old English phrase for blond hair – Faeger-feahs. The oldest settlements in Fairfax County were along the Potomac River, George Washington settled in Fairfax County and built his home, Mount Vernon, facing the river. Gunston Hall, the home of George Mason is nearby, modern Fort Belvoir is partly on the estate of Belvoir Manor, built along the Potomac by William Fairfax in 1741. Thomas Fairfax, 6th Lord Fairfax of Cameron, the member of the British nobility ever to reside in the colonies. The Belvoir mansion and several of its outbuildings were destroyed by fire immediately after the Revolutionary War in 1783, in 1757, the northwestern two-thirds of Fairfax County became Loudoun County. In 1789, part of Fairfax County was ceded to the government to form Alexandria County of the District of Columbia. Alexandria County was returned to Virginia in 1846, reduced in size by the secession of the independent city of Alexandria in 1870, the Fairfax County town of Falls Church became an independent city in 1948. The Fairfax County town of Fairfax became an independent city in 1961, Fairfax County was an important region in the Civil War. The Battle of Chantilly or Ox Hill, during the campaign as the second Battle of Bull Run, was fought within the county. Other areas of activity included Minors Hill, Munsons Hill, and Uptons Hill, on the eastern border, overlooking Washington. The federal governments growth during and after World War II spurred rapid growth in the county, other large businesses continued to settle in Fairfax County and the opening of Tysons Corner Center spurred the rise of Tysons Corner. The technology boom and a steady government-driven economy also created rapid growth, the economy has also made Fairfax County one of the nations wealthiest counties

Fairfax County, Virginia
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The Old Fairfax County Courthouse located in Fairfax City (photo from late 2010)
Fairfax County, Virginia
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Piney Branch Mill, southeast of Fairfax city, Historic American Buildings Survey
Fairfax County, Virginia
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CIA headquarters in Langley
Fairfax County, Virginia
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Fairfax County is, along with Washington, a "core" employment jurisdiction of the Washington Metropolitan Area as indicated by this map. A U.S. Department of Labor study published in 2007 described Fairfax County as the second "economic pillar" of the Washington-area economy, along with the District of Columbia. The county has been described in Time as "one of the great economic success stories of our time."

4.
Waterfall
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A waterfall is a place where water flows over a vertical drop or a series of drops in the course of a stream or river. Waterfalls also occur where meltwater drops over the edge of an iceberg or ice shelf. Waterfalls are commonly formed in the course of a river. At these times the channel is narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, as the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream, often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it. The rate of retreat for a waterfall can be as high as one, eventually, the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. Waterfalls normally form in an area due to erosion. After a long period of being formed, the water falling off the ledge will retreat. Eventually, as the pit grows deeper, the waterfall collapses to be replaced by a steeply sloping stretch of river bed, a river sometimes flows over a large step in the rocks that may have been formed by a fault line. Waterfalls can occur along the edge of a trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon, another reason hanging valleys may form is where two rivers join and one is flowing faster than the other. Waterfalls can be grouped into ten classes based on the average volume of water present on the fall using a logarithmic scale. Class 10 waterfalls include Niagara Falls, Paulo Afonso Falls and Khone Falls, young Wrote Waterfalls, form and process this work made waterfalls a much more serious topic for research for modern Geoscientists. Ledge waterfall, Water descends vertically over a cliff, maintaining partial contact with the bedrock. Block/Sheet. Classical, Ledge waterfalls where fall height is equal to stream width. Curtain, Ledge waterfalls which descend over a larger than the width of falling water stream

5.
Potomac River
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The Potomac River /pəˈtoʊmək/ is located along the mid-Atlantic Ocean coast of the United States and flows into the Chesapeake Bay. The river is approximately 405 miles long, with an area of about 14,700 square miles. In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States, over 5 million people live within the Potomac watershed. The river forms part of the borders between Maryland and Washington, D. C. on the left descending bank and West Virginia and Virginia on the right descending bank. The majority of the lower Potomac River is part of the State of Maryland, exceptions include a small tidal portion within the District of Columbia, and the border with Virginia being delineated from point to point. Except for a portion of its headwaters in West Virginia. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, the Potomac River runs 405 miles from the Fairfax Stone in West Virginia on the Allegheny Plateau to Point Lookout, Maryland, and drains 14,679 square miles. The length of the river from the junction of its North and South Branches to Point Lookout is 302 miles, the average flow is 10,800 ft³/s. The largest flow recorded on the Potomac at Washington, D. C. was in March 1936 when it reached 425,000 ft³/s. The lowest flow recorded at the same location was 600 ft³/s in September,1966. The source of the North Branch is at the Fairfax Stone located at the junction of Grant, Tucker, the source of the South Branch is located near Hightown in northern Highland County, Virginia. The rivers two branches converge just east of Green Spring in Hampshire County, West Virginia, to form the Potomac. Once the Potomac drops from the Piedmont to the Coastal Plain at Little Falls, tides further influence the river as it passes through Washington, D. C. salinity in the Potomac River Estuary increases thereafter with distance downstream. The estuary also widens, reaching 11 statute miles wide at its mouth, Potomac is a European spelling of Patowmeck, the Algonquian name of a Native American village, perhaps meaning something brought. Native Americans had different names for different parts of the river, calling the river above Great Falls Cohongarooton, meaning honking geese and Patawomke below the fall, meaning river of swans. The spelling of the name has many forms over the years from Patawomeke to Patawomeck, Patowmack. The rivers name was decided upon as Potomac by the Board on Geographic Names in 1931. The river itself is at least two years old, likely extending back ten to twenty million years before present when the Atlantic Ocean lowered and exposed coastal sediments along the fall line

6.
Washington, D.C.
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Washington, D. C. formally the District of Columbia and commonly referred to as Washington, the District, or simply D. C. is the capital of the United States. The signing of the Residence Act on July 16,1790, Constitution provided for a federal district under the exclusive jurisdiction of the Congress and the District is therefore not a part of any state. The states of Maryland and Virginia each donated land to form the federal district, named in honor of President George Washington, the City of Washington was founded in 1791 to serve as the new national capital. In 1846, Congress returned the land ceded by Virginia, in 1871. Washington had an population of 681,170 as of July 2016. Commuters from the surrounding Maryland and Virginia suburbs raise the population to more than one million during the workweek. The Washington metropolitan area, of which the District is a part, has a population of over 6 million, the centers of all three branches of the federal government of the United States are in the District, including the Congress, President, and Supreme Court. Washington is home to national monuments and museums, which are primarily situated on or around the National Mall. The city hosts 176 foreign embassies as well as the headquarters of international organizations, trade unions, non-profit organizations, lobbying groups. A locally elected mayor and a 13‑member council have governed the District since 1973, However, the Congress maintains supreme authority over the city and may overturn local laws. D. C. residents elect a non-voting, at-large congressional delegate to the House of Representatives, the District receives three electoral votes in presidential elections as permitted by the Twenty-third Amendment to the United States Constitution, ratified in 1961. Various tribes of the Algonquian-speaking Piscataway people inhabited the lands around the Potomac River when Europeans first visited the area in the early 17th century, One group known as the Nacotchtank maintained settlements around the Anacostia River within the present-day District of Columbia. Conflicts with European colonists and neighboring tribes forced the relocation of the Piscataway people, some of whom established a new settlement in 1699 near Point of Rocks, Maryland. 43, published January 23,1788, James Madison argued that the new government would need authority over a national capital to provide for its own maintenance. Five years earlier, a band of unpaid soldiers besieged Congress while its members were meeting in Philadelphia, known as the Pennsylvania Mutiny of 1783, the event emphasized the need for the national government not to rely on any state for its own security. However, the Constitution does not specify a location for the capital, on July 9,1790, Congress passed the Residence Act, which approved the creation of a national capital on the Potomac River. The exact location was to be selected by President George Washington, formed from land donated by the states of Maryland and Virginia, the initial shape of the federal district was a square measuring 10 miles on each side, totaling 100 square miles. Two pre-existing settlements were included in the territory, the port of Georgetown, Maryland, founded in 1751, many of the stones are still standing

7.
Great Falls Park
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Great Falls Park is a small National Park Service site in Virginia, United States. Situated on 800 acres along the banks of the Potomac River in northern Fairfax County, native American petroglyphs have been discovered within the park on cliffs overlooking Difficult Run. The park visitor center has the bottom portions of two wooden canal lock gates excavated in the 1980s from the canal, the gates survived from at least the 1830s and were found during restoration projects on stonework which were erected for the canal locks. Stonemason marks found on the stones are unique to each artisan and are identical to some found in stones of the White House. During the construction of the canal, blasting powder, which at the time was essentially gunpowder, was used to blast through solid rocks and this is one of the first known examples of blasting powder being used for engineering purposes anywhere in the world. The canal was never a profitable enterprise, with the completion of the Chesapeake and Ohio Canal on the opposite side of the river, and the oncoming age of railroads, the project was abandoned in 1830. The canal is a Civil Engineering Landmark as well as a Virginia Historic Landmark, along the trails, the ruins of the small town of Matildaville, Virginia can also be found. Between 1906 and 1932, the Great Falls and Old Dominion Railroad and its successor, located at the end of an electric trolley line that began in Georgetown, Washington, D. C. the park contained picnic grounds, a dance pavilion, and a carousel. In the evenings, a searchlight illuminated the falls, the park continues to provide picnic grounds and a visitors center but the carousel that operated between 1954 and 1972 was destroyed by a flood caused by Hurricane Agnes. The George Washington Memorial Parkway was developed to ensure the linkage of George Washingtons most visited places. Great Falls Park was a part of the Northern Virginia Parks system and was transferred to the NPS in 1966, access the park by exiting Interstate 495 at Georgetown Pike and head west 3 miles to Old Dominion Drive. From there follow the signs north 1 mile to the park entrance, there is a $10 entrance fee per car for visitors who drive into the park. The park is only during daylight hours. The park has several viewing platforms that provide visitors with vantage points overlooking the falls, the NPS operates a visitor center near the falls. Fifteen miles of hiking trails encompass the park and follow a small stream known as Difficult Run, rock climbers frequent the cliffs in Mather Gorge above the Potomac. The park contains a picnic area and sufficient parking for 600 vehicles. On busy weekends all the parking may fill up by early in the morning, creating delays, the NPS does not permit camping in the park. The falls total 76 feet over a series of major cascades, the Great Falls are rated Class 5-6 Whitewater according to the International Scale of River Difficulty

Great Falls Park
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Great Falls Park
Great Falls Park
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Great Falls (climbing area)
Great Falls Park
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Panoramic view of Great Falls of the Potomac River
Great Falls Park
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Great Falls Park in the early 1900s

8.
National Park Service
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It was created on August 25,1916, by Congress through the National Park Service Organic Act and is an agency of the United States Department of the Interior. As of 2014, the NPS employs 21,651 employees who oversee 417 units, the National Park Service celebrated its centennial in 2016. National parks and national monuments in the United States were originally individually managed under the auspices of the Department of the Interior, the movement for an independent agency to oversee these federal lands was spearheaded by business magnate and conservationist Stephen Mather, as well as J. Horace McFarland. With the help of journalist Robert Sterling Yard, Mather ran a publicity campaign for the Department of the Interior and they wrote numerous articles that praised the scenic and historic qualities of the parks and their possibilities for educational, inspirational, and recreational benefits. This campaign resulted in the creation of a National Park Service, Mather became the first director of the newly formed NPS. On March 3,1933, President Herbert Hoover signed the Reorganization Act of 1933, the act would allow the President to reorganize the executive branch of the United States government. It wasnt until later that summer when the new President, Franklin D. Roosevelt, President Roosevelt agreed and issued two Executive orders to make it happen. In 1951, Conrad Wirth became director of the National Park Service, the demand for parks after the end of the World War II had left the parks overburdened with demands that could not be met. In 1952, with the support of President Dwight D. Eisenhower, he began Mission 66, New parks were added to preserve unique resources and existing park facilities were upgraded and expanded. In 1966, as the Park Service turned 50 years old, emphasis began to turn from just saving great and wonderful scenery, Director George Hartzog began the process with the creation of the National Lakeshores and then National Recreation Areas. Since its inception in 1916, the National Park Service has managed each of the United States national parks, Yellowstone National Park was the first national park in the United States. In 1872, there was no government to manage it. Yosemite National Park began as a park, the land for the park was donated by the federal government to the state of California in 1864 for perpetual conservation. Yosemite was later returned to federal ownership, at first, each national park was managed independently, with varying degrees of success. In Yellowstone, the staff was replaced by the U. S. Army in 1886. Due to the irregularities in managing these national treasures, Stephen Mather petitioned the government to improve the situation. In response, Secretary of the Interior Franklin K. Lane challenged him to lobby for creating a new agency, Mather was successful with the ratification of the National Park Service Organic Act in 1916. Later, the agency was given authority over other protected areas, the National Park System includes all properties managed by the National Park Service

National Park Service
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In 1916, a portfolio of nine major parks was published to generate interest. Printed on each brochure was a map showing the parks and principal railroad connections.
National Park Service
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National Park Service Arrowhead
National Park Service
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In 1934, a series of ten postage stamps were issued to commemorate the reorganization and expansion of the National Park Service.
National Park Service
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Grand Canyon National Park, south rim of canyon.

9.
Chesapeake and Ohio Canal
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The canals principal cargo was coal from the Allegheny Mountains. Construction on the 184. 5-mile canal began in 1828 and ended in 1850 with the completion of a 50-mile stretch to Cumberland, a planned section to the Ohio River at Pittsburgh was never built. The canal way is now maintained as the Chesapeake and Ohio Canal National Historical Park, after the American Revolutionary War, George Washington was the chief advocate of using waterways to connect the Eastern Seaboard to the Great Lakes and the Ohio River. In 1785, Washington founded the Potowmack Company to improve the navigability of the Potomac River and his company built five skirting canals around the major falls, Little Falls, Great Falls in Virginia, Seneca Falls, Paynes Falls of the Shenendoah, and Houses Falls near Harpers Ferry. These canals allowed an easy downstream float, upstream journeys, propelled by pole, were harder, several kinds of watercraft were used on the Patowmack Canal and in the Potomac River. Gondolas were 60-by-10-foot log rafts usually sold at journeys end for their wood by their owners, sharpers were flat-bottomed boats,60 by 7 feet, usable only on high-water days, about 45 days per year. As early as 1820, plans were being laid for a canal to link the Ohio River, in early March 1825, President James Monroe signed the bill chartering the construction of the C&O Canal as one of the last acts of his presidency. Free from taxation, the company was required to have 100 miles in use in five years. The canal was engineered to have a 2 mph water current, supplying the canal, the eastern section was the only part to be completed In October 23,1826, the engineers submitted the study, presenting the proposed canal route in three sections. The total estimated price tag, more than $22 million, dampened the enthusiasm of many supporters, who were expecting more like $4 million to $5 million. At a convention in December 1826, they attempted to discredit the engineers report, geddes and Roberts were hired to make another report, which they gave in 1828, $4,479,346.93 for Georgetown to Cumberland. With those numbers to them, the stockholders formally organized the Chesapeake. In the end, the construction cost to Cumberland in 1850 was $11,071,075.21. The cost overrun of the proposal was about 51% thus showing that the original engineers estimate was good. In 1824, the holdings of the Patowmack Company were ceded to the Chesapeake, according to historians, those financial resources were expended until the State had prostrated itself on its own credit. The C&Os first chief engineer was Benjamin Wright, formerly chief engineer of the Erie Canal, a groundbreaking ceremony was held on July 4,1828, attended by U. S. president John Quincy Adams. The ceremony was held near Georgetown, at the canals eventual 5. 64-mile mark near Lock 6, the end of the Little Falls skirting canal. At the groundbreaking, there was argument over the eastern end of the canal

10.
Billy Goat Trail
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Section A of the trail, by far the most popular, is on Bear Island and traverses rough and rocky terrain, including a steep climb along a cliff face along the Potomac Rivers Mather Gorge. At another point in the trail, hikers are required to scramble over, sections B and C are less strenuous, section B requires only one brief scramble, and section C has none. Most of the trail is marked with light blue trail blazes. Section A is best accessed from the Great Falls Tavern Visitor Center, Section B and Section C are best accessed from Carderock, Maryland. All sections of the trail are free, although a fee is charged when entering and parking near the Great Falls Tavern Visitor Center. No fee is charged when parking near Carderock, dogs are not allowed on Section A, nor on Olmsted Island, but are permitted on a leash at all times everywhere else in the park. It takes about 2 1/2 hours to do the Section A loop from the parking lot, the three sections of the trail do not connect directly with each other, but are connected to each other by the towpath along the C&O Canal. The end point of section C is about 2.75 miles southeast along the towpath from the point of section A. Pictures are approximately upstream to downstream on the trail, Great Falls Trail Descriptions from the National Park Service website Great Falls Trail Map, Page 1 and Page 2 from the National Park Service website The Washington Post

11.
Olmsted Island
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It is a part of Potomac, Maryland. Named for Frederick Law Olmsted, Jr, the island is very rocky and has steep cliffs that face the river, where it has been eroded over time. It also has trees and vegetation, one might also spy a heron, small lizard or wild goose here. The total area of the island is no more than 0.2 square kilometers, a fenced-in wooden tourist walkway winds along the southern part of the island. For the purpose of protecting the natural wildlife, visitors are not allowed to leave the tourist walkway. The tourist walkway eventually ends in a scenic overlook platform that has a view of the Great Falls of the Potomac River. The next big flood will wash them away again and you may see a rare species in one area, then the floods will come through and wash it out. Some other plants grow there instead. This is one of the most biologically diverse habitats within the national park system. Satellite imagery of Olmsted Island on Google Maps, if you look carefully towards the southern end of the island you can see the tourist walkway winding its way and finally ending in the overlook platform at Great Falls

Olmsted Island
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Image 1: A scenic overlook is built into a rock on Olmsted Island
Olmsted Island
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Image 2: Close up of the plaque in Image 1
Olmsted Island
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Image 3: The view from the tourist walkway on Olmsted Island overlooking the Great Falls of the Potomac River.

12.
Kayaking
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Kayaking is the use of a kayak for moving across water. It is distinguished from canoeing by the position of the paddler. A kayak is a low-to-the-water, canoe-like boat in which the paddler sits facing forward, legs in front, using a paddle to pull front-to-back on one side. Most kayaks have closed decks, although sit-on-top and inflatable kayaks are growing in popularity as well, kayaks were created thousands of years ago by the Inuit, formerly known as Eskimos, of the northern Arctic regions. They used driftwood and sometimes the skeleton of whale, to construct the frame of the kayak, the main purpose for creating the kayak, which literally translates to hunters boat was for hunting and fishing. The kayaks stealth capabilities, allowed for the hunter to sneak up behind animals on the shoreline, by the mid-1800s the kayak became increasingly popular and the Europeans became interested. German and French men began kayaking for sport, in 1931, a man named Adolf Anderle became the first person to kayak down the Salzachofen Gorge, this is where the birthplace of modern-day white-water kayaking is believed to have begun. Kayak races were introduced in the Berlin Olympic Games in 1936, in the 1950s fiberglass kayaks were developed and commonly used, until 1980s when polyethylene plastic kayaks came about. Kayaking progressed as a sport in the U. S. until the 1970s. Now, more than 10 white water kayaking events are featured in the Olympics, kayaks can also be classified by their design and the materials from which they are made. Each design has its specific advantage, including performance, manoeuvrability, stability, kayaks can be made of metal, fibreglass, wood, plastic, fabrics, and inflatable fabrics such as PVC or rubber, and more recently expensive but feather light carbon fiber. Each material also has its specific advantage, including strength, durability, portability, flexibility, resistance to ultraviolet, for example, wooden kayaks can be created from kits or built by hand. Stitch and glue, plywood kayaks can be lighter than any other material except skin-on frame, inflatable kayaks, made from lightweight fabric, can be deflated and easily transported and stored, and considered to be remarkably tough and durable compared to some hard-sided boats. There are many types of kayaks used in water and white water kayaking. The sizes and shapes vary drastically depending on type of water to be paddled on. The second set of essentials for kayaking is an off-set paddle where the blades are tilted to help reduce wind resistance while the other blade is being used in the water. These vary in length and also depending on the intended use, height of the paddler and often. Proper clothing such as a dry suit, wet suit or spray top also help protect kayakers from cold water or air temperatures, sit on top kayaks place the paddler in an open, shallowly-concave deck above the water level

13.
Whitewater rafting
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Rafting and white water rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water, dealing with risk and the need for teamwork is often a part of the experience. It is considered a sport, and can be fatal. The International Rafting Federation, often referred to as the IRF, is the body which oversees all aspects of the sport. Otherwise known as the International Scale of River Difficulty, below are the six grades of difficulty in white water rafting and they range from simple to very dangerous and potential death or serious injuries. Class 1, Very small rough areas, might require slight maneuvering, Class 2, Some rough water, maybe some rocks, might require some maneuvering. Class 3, Small waves, maybe a small drop, Class 6, Class 6 rapids are considered to be so dangerous that they are effectively unnavigable on a reliably safe basis. Traversing a Class 6 rapid has an increased likelihood of ending in serious injury or death compared to lesser classes. Rafts in white water are very different vehicles than canoes or kayaks and have their own techniques to maneuver through whitewater obstacles. Punching – Rafts carry great momentum, and on rivers hydraulics that are dodged by canoes and this involves the rafting crew paddling the raft to give it enough speed to push through the hydraulic without getting stopped. High siding – If a raft is caught in a hydraulic it will quickly go sideways. In this position the rafters may be able to use the draw stroke to pull the raft out of the head, low siding- more of a professional maneuver sometimes used at LOW water to slide through a channel less than the size of your craft. Dump truck – Rafts are inherently stable craft because of their size and low center of mass, in the industry, if a raft dumps some or all of its passengers but remains upright, it is said to have dump-trucked. Left over right or right over left – Rafts almost always flip side over side, If the left tube rises over the right tube, the raft is said to have flipped left over right and vice versa. Taco – If a raft is soft, or under-inflated, it may taco, Rafts are said to have tacoed if the middle of the raft buckles and the front of the raft touches or nearly touches the back of the raft. This is often a result of surfing in a hydraulic, a reverse taco is when the nose or stern of the raft is pulled down under water and buckles to touch the middle, back or nose of the raft. End over end – Occasionally rafts will flip end over end and this is usually after the raft has dump-trucked to lighten the load, allowing the water to overcome the weight of the boat, flipping it vertically before it lands upside down. Rafts will more often taco and turn sideways, making an end-over-end flip very rare in most rafts, downstream flip – A raft capsizes after encountering an obstacle, such as a rock, a feature like a hydraulic, or even another raft

14.
Rock climbing
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Rock climbing is an activity in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a usually pre-defined route without falling. Due to the length and extended endurance required and because accidents are likely to happen on descent than ascent. It is very rare for a climber to downclimb, especially on the larger multiple pitches, professional Rock climbing competitions have the objectives of either completing the route in the quickest possible time or attaining the farthest point on an increasingly difficult route. Scrambling, another activity involving the scaling of hills and similar formations, is similar to rock climbing, however, rock climbing is generally differentiated by its sustained use of hands to support the climbers weight as well as to provide balance. Rock climbing is a physically and mentally demanding sport, one that often tests a climbers strength, endurance, agility and it can be a dangerous activity and knowledge of proper climbing techniques and usage of specialized climbing equipment is crucial for the safe completion of routes. Because of the range and variety of rock formations around the world. Paintings dating from 200 BC show Chinese men rock climbing China woop woop, in early America, the cliff-dwelling Anasazi in the 12th century were thought to be excellent climbers. Early European climbers used rock climbing techniques as a required to reach the summit in their mountaineering exploits. In the 1880s, European rock climbing become an independent pursuit outside of mountain climbing, Rock climbing evolved gradually from an alpine necessity to a distinct athletic activity. However, climbing techniques, equipment and ethical considerations have evolved steadily, today, free climbing, climbing using holds made entirely of natural rock while using gear solely for protection and not for upward movement, is the most popular form of the sport. Free climbing has since divided into several sub-styles of climbing dependent on belay configuration. Over time, grading systems have also created in order to compare more accurately the relative difficulties of the rock climbs. In How to Rock Climb, John Long notes that for moderately skilled climbers simply getting to the top of a route is not enough, in rock climbing, style refers to the method of ascending the cliff. There are three styles of climbing, on-sight, flash, and redpoint. To on-sight a route is to ascend the wall without aid or any foreknowledge and it is considered the way to climb with the most style. Flashing is similar to on-sighting, except that the climber has previous information about the route including talking about the beta with other climbers, redpointing means to make a free ascent of the route after having first tried it. Free climbing is typically divided into styles that differ from one another depending on the choice of equipment used

15.
Hiking
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Hiking is the preferred term, in Canada and the United States, for a long, vigorous walk, usually on trails, in the countryside, while the word walking is used for shorter, particularly urban walks. On the other hand, in the United Kingdom, and the Republic of Ireland, the word hiking is also often used in the UK, along with rambling, hillwalking, and fell walking. The term bushwalking is endemic to Australia, having been adopted by the Sydney Bush Walkers club in 1927, in New Zealand a long, vigorous walk or hike is called tramping. It is an activity with numerous hiking organizations worldwide. In the United States, Canada, the Republic of Ireland, a day hike refers to a hike that can be completed in a single day. However, in the United Kingdom, the walking is also used, as well as rambling. In Northern England, Including the Lake District and Yorkshire Dales, fellwalking describes hill or mountain walks, hiking sometimes involves bushwhacking and is sometimes referred to as such. This specifically refers to walking through dense forest, undergrowth, or bushes. In extreme cases of bushwhacking, where the vegetation is so dense that human passage is impeded, the Australian term bushwalking refers to both on and off-trail hiking. Common terms for hiking used by New Zealanders are tramping, walking or bushwalking, trekking is the preferred word used to describe multi-day hiking in the mountainous regions of India, Pakistan, Nepal, North America, South America, Iran and in the highlands of East Africa. Hiking a long-distance trail from end-to-end is also referred to as trekking, in North America, multi-day hikes, usually with camping, are referred to as backpacking. The idea of taking a walk in the countryside for pleasure developed in the 18th-century, in earlier times walking generally indicated poverty and was also associated with vagrancy. Thomas West, an English priest, popularized the idea of walking for pleasure in his guide to the Lake District of 1778. To this end he included various stations or viewpoints around the lakes, published in 1778 the book was a major success. Another famous early exponent of walking for pleasure, was the English poet William Wordsworth, in 1790 he embarked on an extended tour of France, Switzerland, and Germany, a journey subsequently recorded in his long autobiographical poem The Prelude. His famous poem Tintern Abbey was inspired by a visit to the Wye Valley made during a tour of Wales in 1798 with his sister Dorothy Wordsworth. Wordsworths friend Coleridge was another keen walker and in the autumn of 1799, he and Wordsworth undertook a three weeks tour of the Lake District. John Keats, who belonged to the generation of Romantic poets began, in June 1818, a walking tour of Scotland, Ireland

16.
Mather Gorge
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Mather Gorge is a river gorge south and just downriver of Great Falls in the state of Maryland bordering Virginia. The Maryland land side of the gorge is Bear Island, part of the Chesapeake and Ohio Canal National Historical Park, both parks are National Park Service sites. The gorge is named after Stephen Mather, the first director of the National Park Service, the gorge is cut by the Potomac River and is, for the most part, lined on both sides by cliffs. Towards the southern end of the gorge, the cliffs become tree-lined bluffs as the gorge widens out into the wider and larger Potomac Gorge, at Little Falls, the Potomac river crosses the fall line as it leaves the Appalachian Piedmont and enters the Atlantic Coastal Plain. Hiking is an activity with many trails along and near the gorge. On the Maryland side, in the C&O Canal National Historical Park, the River Trail in Great Falls Park follows the gorge on the Virginia side. It is also a rock climbing attraction as the cliff heights. Generally, most of the rock climbing occurs on the cliffs of the Virginia side of the gorge, below the Observation Decks. Whitewater kayaking and canoeing is also popular within the gorge. From Great Falls to the Difficult Run Rapids, the gorge contains Class I to Class VI whitewater rapids

Mather Gorge
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Mather Gorge from the Virginia side. The Potomac River lies fully within Maryland.
Mather Gorge
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Students scrambling over boulders on the Billy Goat Trail. Mather Gorge is on the left.

17.
Metamorphic rock
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Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. The original rock is subjected to heat and pressure, causing profound physical and/or chemical change, the protolith may be a sedimentary, an igneous, or even an existing type of metamorphic rock. Metamorphic rocks make up a part of the Earths crust. They are classified by texture and by chemical and mineral assemblage and they may be formed simply by being deep beneath the Earths surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure and they are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earths interior. The study of rocks provides information about the temperatures and pressures that occur at great depths within the Earths crust. Some examples of rocks are gneiss, slate, marble, schist. Metamorphic minerals are those that only at the high temperatures and pressures associated with the process of metamorphism. These minerals, known as index minerals, include sillimanite, kyanite, staurolite, andalusite, and some garnet. Other minerals, such as olivines, pyroxenes, amphiboles, micas, feldspars, and quartz, may be found in metamorphic rocks and these minerals formed during the crystallization of igneous rocks. They are stable at temperatures and pressures and may remain chemically unchanged during the metamorphic process. However, all minerals are only within certain limits. The change in the size of the rock during the process of metamorphism is called recrystallization. Both high temperatures and pressures contribute to recrystallization, high temperatures allow the atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. The layering within metamorphic rocks is called foliation, and it occurs when a rock is being shortened along one axis during recrystallization. This causes the platy or elongated crystals of minerals, such as mica and chlorite and this results in a banded, or foliated rock, with the bands showing the colors of the minerals that formed them. Textures are separated into foliated and non-foliated categories, foliated rock is a product of differential stress that deforms the rock in one plane, sometimes creating a plane of cleavage. For example, slate is a metamorphic rock, originating from shale

18.
Schist
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Schist is a medium-grade metamorphic rock with medium to large, flat, sheet-like grains in a preferred orientation. It is defined by having more than 50% platy and elongated minerals, often finely interleaved with quartz and these lamellar minerals include micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a form called quartz schist is produced. Schist forms at a temperature and has larger grains than phyllite. Geological foliation with medium to large grained flakes in a preferred orientation is called schistosity. The names of various schists are derived from their mineral constituents, for example, schists rich in mica are called mica schists and include biotite or muscovite. Most schists are mica schists, but graphite and chlorite schists are also common, Schists are also named for their prominent or perhaps unusual mineral constituents, as in the case of garnet schist, tourmaline schist, and glaucophane schist. The individual mineral grains in schist, drawn out into flaky scales by heat and pressure, Schist is characteristically foliated, meaning that the individual mineral grains split off easily into flakes or slabs. Most schists are derived from clays and muds that have passed through a series of processes involving the production of shales, slates and phyllites as intermediate steps. Certain schists are derived from fine-grained igneous rocks such as basalts, before the mid-18th century, the terms slate, shale and schist were not sharply differentiated by those involved with mining. In the context of underground mining, shale was frequently referred to as slate well into the 20th century. During metamorphism, rocks which were originally sedimentary, igneous or metamorphic are converted into schists, if the composition of the rocks was originally similar, they may be very difficult to distinguish from one another if the metamorphism has been great. A quartz-porphyry, for example, and a fine grained feldspathic sandstone, usually, however, it is possible to distinguish between sedimentary and igneous schists and gneisses. If, for example, the district occupied by these rocks has traces of bedding, clastic structure, or unconformability. In other cases intrusive junctions, chilled edges, contact alteration or porphyritic structure may prove that in its original condition a metamorphic gneiss was an igneous rock. Such rocks as limestones, dolomites, quartzites and aluminous shales have very definite chemical characteristics which distinguish them even when completely recrystallized, the schists are classified principally according to the minerals they consist of and on their chemical composition. For example, many metamorphic limestones, marbles, and calc-schists, with crystalline dolomites, contain silicate minerals such as mica, tremolite, diopside, scapolite, quartz and they are derived from calcareous sediments of different degrees of purity. Another group is rich in quartz, with amounts of white and black mica, garnet, feldspar, zoisite

Schist
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Schist specimen showing the characteristic "scaly" schistose texture, caused by platy micas
Schist
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Microscopic view of garnet-mica-schist in thin section under polarized light with a large garnet crystal (black) in a matrix of quartz and feldspar (white and gray grains) and parallel strands of mica (red, purple and brown).
Schist
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View of cut garnet-mica-schist
Schist
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Manhattan schist from southeastern New York State

19.
Patowmack Canal
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Few ventures were dearer to George Washington than his plan to make the Potomac River navigable as far as the Ohio River Valley. The way, Washington wrote, is easy and dictated by our clearest interest and it is to open a wide door, and make a smooth way for the produce of that Country to pass to our Markets. As a waterway west, the Potomac River could be that door and it was the shortest potential route between tidewater, with access to East Coast and trans-Atlantic trade, and the headwaters of the Ohio River, with access to the western frontier. But both political and physical obstacles had to be overcome, opening the Potomac required cooperation of Virginia and Maryland, both of which bordered the river. In 1784, Washington convinced the states assemblies to establish a company to improve the Potomac between its headwaters near Cumberland, Maryland, and tidewater at Georgetown, the Patowmack Company, organized May 17,1785, drew directors and subscribers from both states. Then, Washington wrote in his diary, the office of president of the Patowmack Company fell upon me and he presided over the project until he became the nations chief executive. Delegates from Virginia and Maryland, meeting at Washingtons home in 1785, drew up the Mount Vernon Compact, the Annapolis Convention led to a general meeting in Philadelphia the following May. Thus, George Washingtons lobbying for interstate cooperation on the Potomac helped prepare the way for the Constitutional Convention of 1787, five skirting canals were made, Little Falls, Great Falls, Seneca Falls, Paynes Falls of the Shenendoah, and House Falls. Three of the canals did not require locks, the Seneca Falls, House Falls, Little Falls used wooden locks, which were not meant to be permanent. At Great Falls, the Potomac presented physical obstacles to travel as well, narrow and winding in places, it drops over 600 feet in 200 miles from Cumberland to sea level. Spring rains swell the river to dangerous heights, summer droughts can render it impassable, to make the river navigable by even shallow draft boats, the Patowmack Company had to dredge portions of the riverbed and skirt five areas of falls. The Little Falls canal ran 3814 yards on the Maryland side of the river, the original locks, near todays Fletchers Boat House, were made of wood, and the canal was finished in 1795. These wooden locks were replaced with stone locks in 1817, and had a lift of 37 feet, the first two locks were named Martha and George. This canal was later repurposed for the Chesapeake and Ohio Canal, partially as Feeder #1, the remains of the stone locks were destroyed when the Baltimore and Ohio Railroad built its Georgetown Branch line c. By far the most demanding task was building a canal with locks to bypass the Great Falls of the Potomac River, roaring over the rocks, the river drops nearly 80 feet in less than a mile. Swift currents, solid rock, and constant financial and labor problems hindered progress on the Patowmack Canal at Great Falls, construction required engineering skills and a labor force not easily found in 18th century America. Crews consisted of unskilled laborers, skilled indentured servants, and slaves rented from nearby plantations, the work was difficult and dangerous. With one of the earliest uses in this country of black-powder blasting, the canal is 1,820 yards long and was completed in 1801, and opened to traffic in 1802

Patowmack Canal
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Lock 1 of the Patowmack Canal. Rounded pebbles and sand fill lock for stabilization. The lock is a total of 18 feet (5 m) deep.
Patowmack Canal
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The Little Falls canal was reused for the Chesapeake and Ohio Canal. Here is part of it.
Patowmack Canal
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Lock 2 of the Patowmack Canal
Patowmack Canal
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Remains of House Falls / Long Canal / C&O Canal

20.
George Washington
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George Washington was an American politician and soldier who served as the first President of the United States from 1789 to 1797 and was one of the Founding Fathers of the United States. He served as Commander-in-Chief of the Continental Army during the American Revolutionary War and he is popularly considered the driving force behind the nations establishment and came to be known as the father of the country, both during his lifetime and to this day. Washington was widely admired for his leadership qualities and was unanimously elected president by the Electoral College in the first two national elections. Washingtons incumbency established many precedents still in use today, such as the system, the inaugural address. His retirement from office two terms established a tradition that lasted until 1940 when Franklin Delano Roosevelt won an unprecedented third term. The 22nd Amendment now limits the president to two elected terms and he was born into the provincial gentry of Colonial Virginia to a family of wealthy planters who owned tobacco plantations and slaves, which he inherited. In his youth, he became an officer in the colonial militia during the first stages of the French. In 1775, the Second Continental Congress commissioned him as commander-in-chief of the Continental Army in the American Revolution, in that command, Washington forced the British out of Boston in 1776 but was defeated and nearly captured later that year when he lost New York City. After crossing the Delaware River in the middle of winter, he defeated the British in two battles, retook New Jersey, and restored momentum to the Patriot cause and his strategy enabled Continental forces to capture two major British armies at Saratoga in 1777 and Yorktown in 1781. In battle, however, Washington was repeatedly outmaneuvered by British generals with larger armies, after victory had been finalized in 1783, Washington resigned as commander-in-chief rather than seize power, proving his opposition to dictatorship and his commitment to American republicanism. Washington presided over the Constitutional Convention in 1787, which devised a new form of government for the United States. Following his election as president in 1789, he worked to unify rival factions in the fledgling nation and he supported Alexander Hamiltons programs to satisfy all debts, federal and state, established a permanent seat of government, implemented an effective tax system, and created a national bank. In avoiding war with Great Britain, he guaranteed a decade of peace and profitable trade by securing the Jay Treaty in 1795 and he remained non-partisan, never joining the Federalist Party, although he largely supported its policies. Washingtons Farewell Address was a primer on civic virtue, warning against partisanship, sectionalism. He retired from the presidency in 1797, returning to his home, upon his death, Washington was eulogized as first in war, first in peace, and first in the hearts of his countrymen by Representative Henry Lee III of Virginia. He was revered in life and in death, scholarly and public polling consistently ranks him among the top three presidents in American history and he has been depicted and remembered in monuments, public works, currency, and other dedications to the present day. He was born on February 11,1731, according to the Julian calendar, the Gregorian calendar was adopted within the British Empire in 1752, and it renders a birth date of February 22,1732. Washington was of primarily English gentry descent, especially from Sulgrave and his great-grandfather John Washington emigrated to Virginia in 1656 and began accumulating land and slaves, as did his son Lawrence and his grandson, Georges father Augustine

George Washington
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George Washington by Gilbert Stuart, 1797
George Washington
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Washington's birthplace
George Washington
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Washington's map, accompanying his Journal to the Ohio (1753–1754)
George Washington
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A mezzotint of Martha Washington, based on a 1757 portrait by Wollaston

21.
Cumberland, Maryland
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Cumberland, officially the City of Cumberland, is a western gateway city and seat of Allegany County, Maryland, and the primary city of the Cumberland, MD-WV Metropolitan Statistical Area. At the 2010 census, the city had a population of 20,859, Cumberland is a regional business and commercial center for Western Maryland and the Potomac Highlands of West Virginia. Historically Cumberland was known as the Queen City, as it was once the second largest in the state, in this role, it supported the settlement of the Ohio Country and the lands in that latitude of the Louisiana Purchase. It also became a center, served by major roads, a canal connecting to Washington, DC. Industry declined after World War II, much of the later urban, business and technological development in the state has been concentrated in eastern coastal cities. Today the Cumberland, MD-WV Metropolitan Statistical Area is one of the poorest in the United States, Cumberland was named by English colonists after the son of King George II, Prince William, the Duke of Cumberland. This area had long been settled for thousands of years by indigenous peoples, the fort was developed along the Great Indian Warpath which tribes used to travel the backcountry. Cumberland also served as an outpost of Colonel George Washington during the French and Indian War, Washington returned as President of the United States in 1794 to Cumberland to review troops assembled to thwart the Whiskey Rebellion. During the 19th century, Cumberland was a key road, railroad and it became the second-largest city in Maryland after the port city of Baltimore. It was nicknamed The Queen City, Cumberland was the terminus, and namesake, of the Cumberland Road that extended westward to the Ohio River at Wheeling, West Virginia. This was the first portion of what would be constructed as the National Road, which eventually reached Ohio, Indiana, the surrounding hillsides were mined for coal and iron ore, and harvested for timber that helped supply the Industrial Revolution. The Chesapeake and Ohio Canal had its terminus here, it was built to improve the movement of goods between the Midwest and Washington, DC, the eastern terminus. Construction of railroads superseded use of the canal, as trains were faster, the city developed as a major manufacturing center, with industries in glass, breweries, fabrics and tinplate. With the restructuring of industry in the Northeast and Mid-Atlantic states following World War II. As a result, its population has declined by nearly half, Cumberland is in the Ridge and Valley physiographic province of the Appalachian Mountains at 39°38′52″N 78°45′46″W, at the junction of the North Branch of the Potomac River and Wills Creek. The majority of the land within the city lies in a created by the junction of these two streams. Interstate 68 runs through the city in an east/west direction, as does Alternate U. S.40, parts of Wills Mountain, Haystack Mountain, and Shriver Ridge are also within the city limits. The abandoned Chesapeake and Ohio Canal is now part of the Chesapeake, the canals towpath is maintained, allowing travel by foot, horse or bicycle between Cumberland and Washington, D. C. a distance of about 185 miles

22.
Chesapeake and Ohio Canal National Historical Park
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The Chesapeake and Ohio Canal National Historical Park is a United States National Historical Park located in the District of Columbia and the states of Maryland and West Virginia. The park was established in 1961 as a National Monument by President Dwight D. Eisenhower to preserve the remains of the Chesapeake and Ohio Canal. The canal and towpath trail extends along the Potomac River from Georgetown, Washington, D. C. to Cumberland, Maryland, in 2013, the path was designated as the first section of U. S. Construction on the Chesapeake and Ohio Canal began in 1828 and ended in 1850 when the canal reached Cumberland, far short of its destination of Pittsburgh. Even though the Baltimore and Ohio Railroad beat the canal to Cumberland by eight years, only in the mid-1870s did larger locomotives and the adoption of air brakes allow the railroad to set rates lower than the canal, sealing its fate. The C&O Canal operated from 1831 to 1924 and served primarily to coal from the Allegheny Mountains to Washington D. C. The canal was closed in 1924, in due to several severe floods that devastated the canals financial condition. In 1938, the canal was obtained from the B&O Railroad by the United States in exchange for a loan from the federal Reconstruction Finance Corporation. The government planned to restore it as a recreation area, additionally, it was viewed as a project for employment for the jobless during the Great Depression. By 1940, the first 22 miles of the canal were repaired and rewatered, from Georgetown to Violettes lock, the first Canal Clipper boat, giving mule driven rides, began in 1941. It was later replaced by the John Quincy Adams in the 1960s, the project was halted when the United States entered World War II and resources were needed elsewhere. In 1941, Harry Athey suggested to President Franklin Roosevelt that the canal could be converted into a highway or a bomb shelter with its roof for landing airplanes. The whole idea was deemed due to the rivers periodic flooding. In 1942, freshets destroyed the rewatered sections of the canal, since this transformed the canal into a concern of national security, in 1942, the War Production Board approved the work. By 1943, Congress had funded the work, repairs were done, the Congress expressed interest in developing the canal and towpath as a parkway. Around 1945, the Corps wanted to remove Dam #8, which would destroy any hope of rewatering the canal above Dam #5, the idea of turning the canal over to automobiles was opposed by some, including United States Supreme Court Associate Justice William O. Douglas. In March 1954, Douglas led an eight-day hike of the towpath from Cumberland to D. C, although 58 people participated in one part of the hike or another, only nine men, including Douglas, hiked the full 184.5 miles. Following this hike, Justice Douglas formed a committee, later to be known as the C&O Canal Association in 1957, serving as the chairman of this group, his commitment to the park proved successful

Chesapeake and Ohio Canal National Historical Park
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Chesapeake and Ohio Canal National Historical Park
Chesapeake and Ohio Canal National Historical Park
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The Cumberland basin at the canal's terminus in 2013. This area has been changed drastically and is almost unrecognizable compared to how it was during the canal's operating days
Chesapeake and Ohio Canal National Historical Park
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Park map
Chesapeake and Ohio Canal National Historical Park
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Work on restoring Lock 16 on the canal in 1939.

23.
NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration efforts have led by NASA, including the Apollo Moon landing missions, the Skylab space station. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the agency is also responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA shares data with various national and international such as from the Greenhouse Gases Observing Satellite. Since 2011, NASA has been criticized for low cost efficiency, from 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1. In the early 1950s, there was challenge to launch a satellite for the International Geophysical Year. An effort for this was the American Project Vanguard, after the Soviet launch of the worlds first artificial satellite on October 4,1957, the attention of the United States turned toward its own fledgling space efforts. This led to an agreement that a new federal agency based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency was created in February 1958 to develop technology for military application. On July 29,1958, Eisenhower signed the National Aeronautics and Space Act, a NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA, earlier research efforts within the US Air Force and many of ARPAs early space programs were also transferred to NASA. In December 1958, NASA gained control of the Jet Propulsion Laboratory, NASA has conducted many manned and unmanned spaceflight programs throughout its history. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter, the experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a space capsule program, and in turn by a two-man capsule program. This goal was met in 1969 by the Apollo program, however, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, to date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude,260,000 feet. The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force, the design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems

NASA
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1963 photo showing Dr. William H. Pickering, (center) JPL Director, President John F. Kennedy, (right). NASA Administrator James Webb in background. They are discussing the Mariner program, with a model presented.
NASA
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Seal of NASA
NASA
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At launch control for the May 28, 1964, Saturn I SA-6 launch. Wernher von Braun is at center.
NASA
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Mercury-Atlas 6 launch on February 20, 1962

24.
Pennsylvania
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Pennsylvania /ˌpɛnsᵻlˈveɪnjə/, officially the Commonwealth of Pennsylvania, is a state located in the northeastern and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle, Pennsylvania is the 33rd largest, the 5th most populous, and the 9th most densely populated of the 50 United States. The states five most populous cities are Philadelphia, Pittsburgh, Allentown, Erie, the state capital, and its ninth-largest city, is Harrisburg. Pennsylvania has 140 miles of shoreline along Lake Erie and the Delaware Estuary. The state is one of the 13 original founding states of the United States, it came into being in 1681 as a result of a land grant to William Penn. Part of Pennsylvania, together with the present State of Delaware, had earlier been organized as the Colony of New Sweden and it was the second state to ratify the United States Constitution, on December 12,1787. Independence Hall, where the United States Declaration of Independence and United States Constitution were drafted, is located in the states largest city of Philadelphia, during the American Civil War, the Battle of Gettysburg, was fought in the south central region of the state. Valley Forge near Philadelphia was General Washingtons headquarters during the winter of 1777–78. Pennsylvania is 170 miles north to south and 283 miles east to west, of a total 46,055 square miles,44,817 square miles are land,490 square miles are inland waters, and 749 square miles are waters in Lake Erie. It is the 33rd largest state in the United States, Pennsylvania has 51 miles of coastline along Lake Erie and 57 miles of shoreline along the Delaware Estuary. Cities include Philadelphia, Reading, Lebanon and Lancaster in the southeast, Pittsburgh in the southwest, the tri-cities of Allentown, Bethlehem, the northeast includes the former anthracite coal mining communities of Scranton, Wilkes-Barre, Pittston City, and Hazleton. Erie is located in the northwest, the state has 5 regions, namely the Allegheny Plateau, Ridge and Valley, Atlantic Coastal Plain, Piedmont, and the Erie Plain. Straddling two major zones, the majority of the state, with the exception of the corner, has a humid continental climate. The largest city, Philadelphia, has characteristics of the humid subtropical climate that covers much of Delaware. Moving toward the interior of the state, the winter climate becomes colder, the number of cloudy days increase. Western areas of the state, particularly locations near Lake Erie, can receive over 100 inches of snowfall annually, the state may be subject to severe weather from spring through summer into fall. Tornadoes occur annually in the state, sometimes in large numbers, the Tuscarora Nation took up temporary residence in the central portion of Pennsylvania ca. Both the Dutch and the English claimed both sides of the Delaware River as part of their lands in America

25.
West Virginia
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West Virginia /ˌwɛst vərˈdʒɪnjə/ is a state located in the Appalachian region of the Southern United States. It is bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the north, West Virginia is the 9th smallest by area, is ranked 38th in population, and has the second lowest household income of the 50 United States. The capital and largest city is Charleston, West Virginia was admitted to the Union on June 20,1863, and was a key Civil War border state. The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States, the unique position of West Virginia means that it is often included in several geographical regions, including the Mid-Atlantic, the Upland South, and the Southeastern United States. It is the state that is entirely within the area served by the Appalachian Regional Commission. The state is noted for its mountains and rolling hills, its historically significant logging and coal mining industries and it is one of the most densely karstic areas in the world, making it a choice area for recreational caving and scientific research. The karst lands contribute to much of the states cool trout waters and it is also known for a wide range of outdoor recreational opportunities, including skiing, whitewater rafting, fishing, hiking, backpacking, mountain biking, and hunting. Many ancient man-made earthen mounds from various mound builder cultures survive, especially in the areas of Moundsville, South Charleston. The artifacts uncovered in these give evidence of village societies and they had a tribal trade system culture that crafted cold-worked copper pieces. The Iroquois drove out other American Indian tribes from the region to reserve the upper Ohio Valley as a ground in the 1670s. Siouan language tribes such as the Moneton had also recorded in the area previously. West Virginia was originally part of the British Virginia Colony from 1607 to 1776, residents of the western and northern counties set up a separate government under Francis Pierpont in 1861, which they called the restored government. Most voted to separate from Virginia and the new state was admitted to the Union in 1863, in 1864 a state constitutional convention drafted a constitution, which was ratified by the legislature without putting it to popular vote. West Virginia abolished slavery and temporarily disfranchised men who had held Confederate office or fought for the Confederacy, West Virginias history has been profoundly affected by its mountainous terrain, numerous and vast river valleys, and rich natural resources. These were all factors driving its economy and the lifestyles of its residents, a 2010 analysis of a local stalagmite revealed that Native Americans were burning forests to clear land as early as 100 BC. Some regional late-prehistoric Eastern Woodland tribes were involved in hunting and fishing, practicing the slash. Another group progressed to the more time-consuming, advanced companion crop fields method of gardening, also continuing from ancient indigenous people of the state, field space and time was given to tobacco growing through to early historic. Maize did not make a contribution to the diet until after 1150 BP

West Virginia
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Thomas Lee, the first manager of the Ohio Company of Virginia.
West Virginia
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Flag
West Virginia
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A celebration at a slave wedding in Virginia, 1838
West Virginia
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On October 24, 1861, when voters from 41 counties voted to form a new state, voter turnout was 34%. The name was subsequently changed from Kanawha to West Virginia.

26.
Donaldson Run
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Donaldson Run is a stream in Arlington County, Virginia. From its source near Marymount University, Donaldson Run flows on a northeastern course, Donaldson Run is surrounded predominantly by forests. Donaldson Run was named after Robert H. Donaldson, one of the farm owners. The land was settled by James Donaldson, then inherited by James son, William. William then passed the land to his son Robert, Robert Donaldsons family worked the farm through the Civil War. Roberts farm wagon carried the name Donaldson & Sons, and the wagon was used to farm produce to Georgetown. Following the outbreak of the Civil War, a ring of forts was built in the area to protect Washington from Confederate forces, during this period most of the trees in the area were felled. The effect on the landscape was devastating, much of the topsoil washed away, resulting in disastrous erosion. One beneficial result, however, was the construction of roads, in the late nineteenth century, this stream served as a popular swimming hole and boat landing. It was first named Rock Run in the nineteenth century. By 1900, the name of the stream had been changed to Donaldson Run, however, the project was not undertaken due to public concern for the environment. In the 1960s, land to the south of Donaldson Run was set aside as parkland, and is now known as Potomac Overlook Regional Park, however foreign greenery such as English ivy, Japanese honeysuckle, bamboo, garlic mustard have taken over much of the native undergrowth. In the forest along the banks of Donaldson Run, there are a number of species including deer, possums, raccoons, woodchucks, foxes, squirrels, flying squirrels, bats, shrews. There is a nature trail along Donaldson Run through Zachary Taylor Park with several scenic footbridges. Donaldson Run flows down the Potomac Palisades, making a 30-foot drop before reaching the Potomac, Potomac Overlook Park has a nature center and a number of exhibits featuring local wildlife and local history. List of rivers of Virginia Bellevue Forest History

Donaldson Run
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Donaldson Run

27.
Rock Creek (Potomac River)
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Rock Creek is a free-flowing tributary of the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The creek is 32.6 miles long, with an area of about 76.5 square miles. The last quarter-mile of the creek is affected by tides, the creek rises from a spring near Laytonsville in Montgomery County, in the U. S. state of Maryland, and joins the Potomac near Georgetown and the Watergate in Washington, D. C. Beginning in the Derwood–Rockville area in Maryland, the flows through Rock Creek Regional Park southward to the D. C. boundary. The Chesapeake and Ohio Canal joins Rock Creek in Georgetown, at the Tidewater Lock, the creek empty into the Potomac River. This area, called the Rock Creek Basin by the Canal Company, which included a mole, causeway, subject to silting up, it was dredged several times for the Canals use. The Maryland portion of the watershed comprises the second-largest watershed in Montgomery County, about 21 percent of the creeks watershed is in Washington. Total land usage in the watershed is 896 acres of wetlands or water,22,272 acres of residential and commercial areas,15,488 acres of forest or grasslands, the creek has a fairly steep gradient, with rapid changes in elevation. The man-made Lake Needwood is located on the creek, north of Rockville, in Maryland, most of the northern Rock Creek watershed has good to excellent water quality, according to studies conducted by the county government. In 2004, to water quality in partially developed areas. The southern portion of the Maryland watershed is highly urbanized, most of this portion of the creek and its tributaries have poor water quality. The county is managing several stream restoration projects throughout the watershed, the D. C. segment of Rock Creek also has poor water quality. In addition to typical urban stormwater pollution problems such as runoff from streets and other impervious surfaces, the D. C. government, which has a stormwater discharge permit from the United States Environmental Protection Agency, is improving its stormwater management to raise water quality in Rock Creek. Fish species observed in Rock Creek and its tributaries include eastern blacknose dace, bluntnose minnow, yellow bullhead, satinfin shiner, swallowtail shiner, longnose dace, and American eel. The effort is designed to restore American shad, river herring, an estimated two million fish migrate up the creek each year. The D. C. government completed a project on the Milkhouse Run. As of 2014, ongoing restoration projects in the include the Broad Branch

28.
Piney Branch
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Piney Branch is a tributary of Rock Creek in Washington, D. C. It is the largest tributary located entirely within the Washington city limits, Rock Creek drains to the Potomac River, which empties into the Chesapeake Bay. Piney Branch is a first order stream with a length of 0.75 miles. It is generally about 12 feet wide and 4 inches deep and it is the largest tributary located entirely within the Washington city limits. Piney Branch drains a watershed of about 0.48 square miles or 2,500 acres and its surface stream drainage is augmented by four combined sewer systems that discharge into it. About 5 percent of the consists of forested parkland near its surface stream. The rest of the area is residential, with some light industrial zones. The creek is listed as polluted by 10 chemicals and four metals, lead, copper, zinc and it is spanned by the 16th Street Bridge, the countrys first parabolic arch bridge. In prehistoric times, the valley was a source of quartzite cobbles for toolmaking. One quarry site is located at the bluffs overlooking Piney Branch from the north, dubbed the Piney Branch Quarry Site, it was first examined by archeologist William Henry Holmes in 1889 and 1890. Another investigation begin in 2006 revealed quartzite debitage, whole and broken turtleback “preforms, ”, in the mid-1800s, the creeks valley was the location of the first road through the area that would become Rock Creek Park. Composed of 8- to 10-foot brick and concrete pipes, the Piney Branch Trunk Sewer is one of the major trunk sewers. Project design was slated to start in January 2014 and last one year, as of early 2016, work was to begin in 2017 and last until 2019. List of rivers of Washington, D. C, Piney Branch watershed photos 2009 map of the combined sewer that empties into Piney Branch

29.
Boundary Channel
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Boundary Channel is a channel off the Potomac River in Washington, D. C. The channel begins at the tip of Columbia Island extends southward between Columbia Island and the Virginia shoreline. It curves around the tip of Columbia Island before heading northeast to exit into the Potomac River. At the southwestern tip of Columbia Island, the Boundary Channel widens into the manmade Pentagon Lagoon, Columbia Island is in part natural, and in part man-made. About 1818, Analostan Island was largely rock and quite close to the D. C. shoreline, due to deforestation and increased agricultural use upstream, the river eroded much of the northern bank of the Potomac River and widened the gap between Analostan Island and the shore. Simultaneously, large deposits of silt built up around Analostan Island, by 1838, Analostan had almost doubled in length toward the south. By 1884, the new part of Analostan Island was defined and built up. Gradually, however, the river eroded the center of Analostan Island, between 1911 and 1922, the Potomac River was repeatedly dredged by the United States Army Corps of Engineers to deepen the channel and alleviate flooding. Dredging widened the distance between Analostan/Theodore Roosevelt Island and Columbia Island, dredged material was piled high on Columbia Island, helping to build it higher, lengthen and broaden it, and give it its current shape. The new island received its name about 1918 from an engineer working for the District of Columbia. An anonymous Corps of Engineers officer named the waterway between Columbia Island and Virginia the Boundary Channel, Boundary Channel was further defined in the late 1920s. In 1925, Congress authorized construction of the Arlington Memorial Bridge across the Potomac River, preliminary designs for the bridge showed it terminating on Columbia Island, which necessitated additional expansion of the island. The dredged material was dumped on Columbia Island, by June 30,1927, dredging of the Potomac River and the reshaping of Columbia Island was largely finished. Boundary Channel marks the original Virginia shoreline and it separates Columbia Island to the east from Virginia in the west and south, and is roughly a mile long. The channel is part of the Potomac River, in 1936, Boundary Channel was 100 to 200 feet in width and 4 to 6 feet in depth. No lagoon existed at this time, broundary Channel was changed again after ground was broken for The Pentagon on September 11,1941. The Pentagon was being built on land just south of the Boundary Channel. But the ground to the northwest, north, northeast, and east of the site was so low that, for a time

Boundary Channel
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Map of area surrounding Boundary Channel and the Pentagon Lagoon
Boundary Channel
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Aerial view of the Columbia Island Marina and the Pentagon Lagoon in relationship to The Pentagon and the Potomac River.
Boundary Channel
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Corona image of The Pentagon and part of the Lagoon, 25 September 1967

30.
Tiber Creek
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Tiber Creek or Tyber Creek is a tributary of the Potomac River in Washington, D. C. In the 19th century it was modified to become part of the Washington City Canal, originally called Goose Creek, it was renamed by settler Francis Pope. It was southeast of then Georgetown, Maryland, amid lands that were selected for the City of Washington and it flowed south toward the base of Capitol Hill, then west meeting the Potomac near Jefferson Pier. Using the original Tiber Creek for commercial purposes was part of Pierre Charles LEnfants 1791 Plan of the city intended for the permanent seat of the government of the United States, the idea was that the creek could be widened and channeled into a canal to the Potomac. By 1815 the western portion of the creek became part of the Washington City Canal, by the 1840s, however, because Washington had no separate storm drain and sewer system, the Washington City Canal was notoriously stinky. It had become an open sewer, one of these projects was to enclose Tiber Creek/Washington City Canal. The low-lying topography there contributed to the flooding of the National Archives Building, IRS, during construction of the Ronald Reagan Building, the engineers figured out how to divert the water. But that dewatering then reduced the level underneath the IRS building which caused the wooden piers to lose stability. A pub near Tiber Creeks historic course north of Capitol Hill was named after it, the Bistro Bis restaurant now occupies the Tiber Creek Pubs former location

31.
Washington Channel
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The Washington Channel is a channel that parallels the Potomac River in Washington, D. C. It is located between the Southwest Waterfront on the east side and East Potomac Park on the west side, the channel is two miles long, receives outflow from the Tidal Basin at its north end, and empties into the Anacostia River at Hains Point at its south end. The channels depth ranges from 8.8 feet to 23 feet, the Washington Channels east bank is lined with restaurants, inns, and marinas including Washington Marina, Gangplank Marina, and Capital Yacht Club. The Maine Avenue Fish Market is situated at the end of the channel. The Womens Titanic Memorial, Fort Lesley J. McNair, the National Defense University, as of August 2010, the USS Sequoia—a former United States presidential yacht—is docked at a pier in the Washington Channel. The bill was passed by the House on July 20,2010, nortons bill is part of a larger plan to redevelop the Southwest Waterfront, some goals of which are to extend docks and increase maritime activity just a short eyeshot from the U. S. Capitol building. The Coast Guard, the Navy, and the Army Corps of Engineers have agreed that this transfer will not affect navigation interests or adversely affect navigation safety

Washington Channel
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View of the Washington Channel from the Southwest Waterfront.
Washington Channel
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Aerial view from the south of East Potomac Park and the Washington Channel, ca. 1935.

32.
Anacostia River
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The Anacostia River /ænəˈkɒstiə/ is a river in the Mid Atlantic region of the United States. It flows from Prince Georges County in Maryland into Washington, D. C. where it joins with the Washington Channel to empty into the Potomac River at Buzzard Point and it is approximately 8.7 miles long. The name Anacostia derives from the early history as Nacotchtank. Heavy pollution in the Anacostia and weak investment and development along its banks have led to it becoming what many have called D. C. s forgotten river, in recent years, however, private organizations, local businesses, and the D. C. Maryland and federal governments have made joint efforts to reduce its pollution levels in order to protect the ecologically valuable Anacostia watershed, the mainstem of the Anacostia is formed by the confluence of the Northwest Branch and the Northeast Branch just north of Bladensburg, Maryland. Tributaries of these sources include Sligo Creek, Paint Branch, Little Paint Branch, Indian Creek, Upper Beaverdam Creek, Dueling Branch, tributaries of the mainstem Anacostia include Watts Branch, Lower Beaverdam Creek and Hickory Run. The watershed of the river roughly covers 176 sq mi in eastern Montgomery County and northern Prince Georges County, as well as parts of Washington, on earlier maps, the river was known as the Eastern Branch of the Potomac River until it received its current, official name. The Washington City Canal operated from 1815 until the mid-1850s, initially connecting the Anacostia to Tiber Creek and the Potomac River, the city canal fell into disuse in the late 19th century, and the city government covered over or filled in various sections. One of the biggest problems facing the Anacostia River is raw sewage that enters the river, the sewage creates a public health threat because of fecal coliform bacteria and other pathogens, it also impairs water quality and can create hypoxic conditions that lead to large fish kills. The Anacostia Watershed Society sued the Washington, D. C, water and Sewer Authority in 1999 for allowing more than 2,000,000,000 US gallons of combined sewage and urban runoff to flow into the river via its antiquated combined sewer overflow system. In settling the lawsuit, WASA agreed to invest $140 million on pump station rehabilitation, pipe cleaning and maintenance, the governments of Montgomery County and Prince Georges County also operate stormwater management programs in their respective jurisdictions. In late 2004, AWS and other organizations announced plans to sue the Washington Suburban Sanitary Commission over similar problems with contamination from the Maryland suburbs. According to WSSC, more than 4,000,000 US gallons of raw sewage were released into Anacostia tributaries between January 2001 and June 2004. Another large source of pollution is the Washington Navy Yard. In May 2009, a Bandalong Litter Trap floating litter-control system was placed in the Watts Branch tributary of the Anacostia River as part of Mayor Adrian Fentys Green DC Agenda. In its first year of operation, it removed more than 500 pounds of litter per month from the river. The Bladensburg Waterfront Park, part of the Prince Georges County Department of Parks and Recreation, the Port Towns Community Boathouse at the park is home to the rowing crews of the University of Maryland, The Catholic University of America, and several local high schools. 11th Street Bridges Anacostia Frederick Douglass Memorial Bridge John Philip Sousa Bridge List of rivers of Washington, D. C

33.
Northwest Branch Anacostia River
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Northwest Branch Anacostia River is a 21. 5-mile-long free-flowing stream in Montgomery County and Prince Georges County, Maryland. It is a tributary of the Anacostia River, which flows to the Potomac River, the headwaters of the Northwest Branch are located near the community of Sandy Spring. The stream flows southward for 21.5 miles to its confluence with the Northeast Branch near Bladensburg to form the stem of the Anacostia. The Prince Georges County portion of the watershed includes Adelphi, Langley Park, University Park, Chillum, Hyattsville, Avondale and Brentwood. The total watershed area, including a portion of land in Washington, D. C. is 53.5 square miles. The middle section of the Northwest Branch is referred to as the Rachel Carson Environmental Area and it flows through a small gorge underneath the Capital Beltway between Colesville Road and Adelphi Mill. Located at the end of the Northwest Branch Trail, near the home of noted environmental author Rachel Carson, it is deliberately left rustic. The majority of the Northwest Branch stream valley is a buffer, protected as parkland by the Maryland-National Capital Park. Northwest Branch crosses the fall line between the piedmont and Atlantic coastal plain regions, which forms a small waterfall on the stream near White Oak. The total stream length of Northwest Branch and all tributaries is 75 miles. Of Parks Wheaton Regional Park - Montgomery County Dept. of Parks Anacostia Tributary Trail System - Prince Georges County Dept. of Parks & Recreation

Northwest Branch Anacostia River
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Map of the Anacostia River watershed showing the Northwest Branch

34.
Sligo Creek
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Sligo Creek is a free-flowing tributary of the Northwest Branch of the Anacostia River in Maryland. The creek is approximately 9.1 miles long, with an area of about 11.6 square miles. It also inspired Katherine Paterson to write the Newbery Medal award winning book Bridge to Terabithia, the creek rises in the Kemp Mill section of Silver Spring in Montgomery County and joins with Northwest Branch near the city of Hyattsville in Prince Georges County. The lower portion of the creek has been channelized, elevations in the subwatershed range from 450 feet above sea level to 35 feet at the confluence with Northwest Branch, the average gradient for the course of the creek is 0. 72%. Contributing streams that flow into the creek include Wheaton Branch, Comstock Branch, Takoma Park Branch, Sligo Creek is one of the most heavily urbanized subwatersheds in the Anacostia watershed, with a population density of 7,081 people per mi2. 75% of the watershed is in Montgomery County, 20% is in Prince Georges County, less than 15% of the subwatershed is undeveloped, and only 10% is forested. Less than 0. 01% of the area is wetlands, from its source to the confluence with the Northwest Branch, the creek crosses through the communities of Silver Spring, Wheaton, Takoma Park, Carole Highlands, Chillum and Hyattsville. In these towns, the banks of the creek are in many stretches maintained as public parkland, with grassy lawns, the Sligo Creek Trail, a hiker-biker trail, runs along the creek from Wheaton to the confluence, where it connects with the Anacostia Tributary Trail System. An automobile parkway runs along parts of the creek in Montgomery County. Sligo Creek was named after the crossroads named Sligo founded in the mid 19th century by Irish immigrant workers on the C&O Canal and it may have been named after County Sligo in Ireland. The crossroads was located at Colesville Road and the 7th Street Pike, currently the corner of Colesville Road, at the time of the Civil War, Sligo had a toll gate on the 7th Street Pike, an inn and a post office. A half mile from the Sligo crossroads Colesville Road crosses Sligo Creek, over the years, Sligo Creek has served many purposes for area residents, including powering grist mills and as a drinking water source. In the Takoma Park section of the creek, the remains of a dam, from 1900 to 1930, the waterworks served the city of Takoma Park, as well as Silver Spring, Kensington, and Bethesda. Another dam, located where Flower Avenue crosses Sligo Creek, served Sligo Mill which was located where the current New Hampshire Avenue crosses Sligo Creek, Sligo Mill was built in 1812 by investors that included several members of the prominent Maryland Carroll family. In addition to milling grain for farmers, Sligo Mill distilled whiskey. The mill was demolished in the 1920s, overlooking the dam and millpond for Sligo Mill on the right bank of Sligo Creek, the Glen Sligo Hotel and Wildwood Amusement Park were built in 1900. The hotel and amusement park ceased operations in 1903, Sligo Creek served as the inspiration and title for Sligo River Blues, a song by Takoma Park guitarist John Fahey, who popularized the area amongst folk artists. Another prominent folk guitarist, Al Petteway, composed Sligo Creek while living in the Takoma Park area and this Scots-influenced guitar tune was later featured as the theme song of The National Parks, a PBS miniseries directed by Ken Burns

Sligo Creek
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The creek running through Silver Spring, Maryland

35.
Northeast Branch Anacostia River
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Northeast Branch Anacostia River is a 3. 2-mile-long free-flowing stream in Prince Georges County, Maryland. It is a tributary of the Anacostia River, which flows to the Potomac River, the headwaters of the Northeast Branch are at the confluence of Indian Creek and Paint Branch, located on the eastern edge of the community of College Park. The stream flows southward for about 3 miles to its confluence with the Northwest Branch near Bladensburg to form the mainstem of the Anacostia. Portions of the Paint Branch and Little Paint Branch tributaries also drain the Cloverly, Colesville, Fairland, White Oak, major institutions in the watershed include the Beltsville Agricultural Research Center, University of Maryland, College Park and Greenbelt Park. The total watershed area, including tributaries, is 75.6 square miles, Northeast Branch is located in the Atlantic coastal plain geologic region. The total stream length of Northeast Branch and all tributaries is 12.1 miles

Northeast Branch Anacostia River
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Map of the Anacostia River watershed showing the Northeast Branch

36.
Four Mile Run
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Most of the stretch is parkland and is paralleled by two paved non-motorized transport and recreational trails, the Washington & Old Dominion Railroad Trail and the Four Mile Run Trail. In Arlington, the passes from the Piedmont through the fall line to the Atlantic Coastal Plain in a deep forested valley. The streams eastern section forms the boundary of Arlington County and the City of Alexandria, the stream eventually empties out into the Potomac River immediately south of Reagan National Airport. The name Four Mile Run does not derive from its length, a 2001 documentary film alleged that the name resulted from a misreading of an old map. The documentary stated that an old flour mill near the Potomac gave the stream the name of Flour Mill Run, Four Mile Run runs into the tidal Four Mile Creek within 1 mile of the mouth of the stream. During the colonial period and the 19th century, several watermills existed in, although none of these mills remain intact, the foundation of one is still in place. The mill provided locals with flour ground from corn and wheat that was grown locally, located west of the stream between Columbia Pike and 10th Street South in Arlington, the foundation presently supports an automobile repair shop. General George Washington owned on the southwest side of the stream in the line a large parcel of wooded property which he surveyed in 1785. As part of survey, Washington made a cut in the trunk of an oak tree to mark a corner of his property where a tributary entered the main stream. A portion of this trunk remains preserved in a neighborhood library, from about 1860 to 1968, the Washington and Old Dominion Railroad and its predecessors traveled along most of the streams length in Arlington. The Northern Virginia Regional Park Authoritys Washington and Old Dominion Railroad Trail now travels along the stream on the railroads route. In the late 19th century, a resort at Carlin Springs became a favorite respite for Washingtonians who would ride the train out for bathing and dancing. Carlin Springs was located within the present day Glencarlyn Park, along Four Mile Run, from 1906 to 1915, the Luna Park amusement complex operated on the banks of Four Mile Run near its confluence with the Potomac. According to publicity, it was a fashion plate, featuring ballrooms, restaurants, roller coasters, shoot-the-chutes, circus performances. Early residents frequently cooled off in the pools of Four Mile Run. Not until the 1930s did the county build a sewage system. In June 1972, rains from Hurricane Agnes caused the stream to overflow its banks, as a result of this event, the Army Corps of Engineers channelized the stream in this and other areas, covering the streams natural banks with riprap. Tributaries are listed in order from the source of Four Mile Run to its mouth, gunston Middle School has been involved in protecting and exploring Four Mile Run actively since 2007

Four Mile Run
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Four Mile Run near Arlington's Jennie Dean Park
Four Mile Run
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Carlin Springs Historical Marker

37.
Oxon Creek
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Oxon Creek is a cove on the Potomac River which straddles the border between Washington, D. C. and Prince Georges County, Maryland just north of Interstate 495 at Woodrow Wilson Bridge. The tributary stream is Oxon Run, Oxon Creek is 1.5 miles in length and empties into the Potomac at Goose Island across from the city of Alexandria, Virginia. To the north is the Blue Plains Advanced Wastewater Treatment Plant, the Anacostia Freeway crosses it on a bridge. To the east is Oxon Hill Manor, the unusual spelling is either historical or a reference to Oxfordshire, England

Oxon Creek
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Anacostia Freeway Crossing Oxon Creek to join the Beltway (2007) - Wilson Bridge is to the left

38.
Hunting Creek
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Hunting Creek is a cove and tributary stream of the Potomac River between the City of Alexandria and Fairfax County in Virginia. It is formed by the confluence of Cameron Run and Hooff Run, the community of Huntington takes its name from the creek. Jones Point forms the north side, dyke Marsh is just to the south. The George Washington Memorial Parkway crosses it on a bridge, the creek is sometimes referred to as Great Hunting Creek, to distinguish it from Little Hunting Creek

Hunting Creek
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Hunting Creek seen from the east in 2010; Alexandria is to the right
Hunting Creek
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Hunting Creek from the west in 2015

39.
Cameron Run
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Cameron Run is a 3. 0-mile-long tributary stream of the Potomac River, located in the U. S. state of Virginia. A third-order stream, it is formed by the confluence of Backlick Run and it flows eastward from Alexandria and forms the border between Fairfax County and Alexandria before opening into Hunting Creek and then into the Potomac River. Cameron Run Regional Park, a park, lies along a portion of the stream. Cameron Run is part of the Cameron Run Watershed, which encompasses a total of 44 square miles in Northern Virginia. The Watershed is made up of eight subwatersheds, Tripps Run, Upper Holmes Run, Lower Holmes Run, Turkeycock Run, Backlick Run, Indian Run, Pike Branch, Cameron run flooded in 2000 and again in 2006, devastating some of the low-lying parts of Huntington. Due to increased development in the watershed, peak water flows have increased, too much sediment from the stream, some of it from the Woodrow Wilson Bridge project, has reduced the depth of the channel, causing flooding problems. Local governments and the U. S. Army Corps of Engineers are working on a solution, list of rivers of Virginia Lake Barcroft Northern Virginia Watersheds Wiki

Cameron Run
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Cameron Run seen from the Yellow Line of the Washington Metro, looking downriver towards the Potomac
Cameron Run
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Washington Metro Yellow Line bridge over Cameron Run

40.
Piscataway Creek
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Piscataway Creek is an 18. 6-mile-long tributary of the Potomac River in Prince Georges County, Maryland. The creek is an arm of the Potomac for its final 2.5 miles. Tinkers Creek is a tributary to Piscataway Creek, converging from the north 4.5 miles upstream of the mouth of the Piscataway, the United States Geological Survey records two variant names for Piscataway Creek, Pascattawaye Creek and Puscattuway Creeke. The Fort Washington Light was built to provide guidance for mariners entering Piscataway Creek from the Potomac River, list of Maryland rivers U. S. Geological Survey water data for Piscataway Creek at Piscataway, Maryland NOAA nautical chart 12289 National Park Service – Piscataway Park

Piscataway Creek
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Mouth of Piscataway Creek, as seen from across the Potomac River

41.
Little Hunting Creek
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Little Hunting Creek is a 3. 6-mile-long primarily tidal tributary of the Potomac River located in Fairfax County, Virginia, not to be confused with Hunting Creek farther north. The creek marks the location along the Potomac River where the Washington family built their Mount Vernon plantation during colonial times, the creek is bordered by residential communities in addition to the Mount Vernon property. It is a location for recreational fishing, and much of the wildlife characteristic of the tidal Potomac wetlands can be spotted there. During the time of John Smiths explorations of Virginia in the early 17th century, by the latter part of that century, the land by Little Hunting Creek had come into the hands of John Washington, great-grandfather of George Washington. What was originally known as Little Hunting Creek Plantation eventually became known as George Washingtons Mount Vernon estate, the creek separated the Mansion House Farm to the west from the River Farm to the east. In 1765, when Fairfax Parish was carved out of the existing Truro Parish, in 1929, a bridge was designed as a part of the Mount Vernon Memorial Highway, and completed in 1931. By the 1960s residential communities began to spring up on sides of the creek. The remnants of a treatment plant are situated on the eastern shore of the creek downstream of the North Branch fork. The headwaters of Little Hunting Creek begin in Huntley Meadows Park on the west side of U. S. Route 1, the creek is fed by three major tributaries. The South Branch is located in the southeast portion of what is now the Stratford Landing neighborhood, the North Branch breaks off from the main creek in a northeasterly direction about 1.5 statute miles up from the Potomac River entrance, near the northwestern end of Stratford Landing. Little Hunting Creek is home to wildlife, migratory birds such as mallards, Canada geese, great blue herons, and great egrets are common sights along the creek. Ospreys nest there, usually on top of a post in the creek, bald eagles have been spotted in the area. Muskrats and the occasional beaver have been seen in Little Hunting Creek, fish such as catfish, carp, perch, and largemouth bass are found in the creek. In 2004 Little Hunting Creek became one of the first sites where invasive northern snakehead fish were caught off the Potomac, Little Hunting Creek remains navigable by canoe or kayak at least until the North Branch fork, depending on the tides. There is a road, located in the neighborhood of Stratford Landing, called Thomas J. Stockton Parkway and it is easy to spot any ospreys that may be nesting there. The creek is an excellent site for largemouth bass fishing, in 2004 a debate arose about whether the installation of duck blinds and duck hunting should be permitted on the creek. Swimming is not advised, particularly in light of drownings that have occurred in the vicinity of the stone-arch bridge, list of rivers of Virginia Little Hunting Creek, Inc

Little Hunting Creek
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Little Hunting Creek, viewed from its east bank looking south
Little Hunting Creek
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Colonial-era map of George Washington's estates surrounding Little Hunting Creek, including the Mount Vernon manor. The South Branch and part of the North Branch of the creek are visible.
Little Hunting Creek
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Ospreys and Canada geese on Little Hunting Creek

42.
Pohick Creek
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Pohick Creek is a 14. 0-mile-long tributary stream of the Potomac River in Fairfax County in the U. S. state of Virginia. It takes its name from the Pohick Native American tribe once prevalent in the area. Pohick Creek is a stream for whitewater kayaking, rafting. Several tributaries of the Pohick Creek are impounded by dams constructed under the Watershed Protection and Flood Prevention Act to prevent soil erosion, originally eight dams were planned, but from 1970 to 1985, only six were actually built. Lake Braddock was the first dam built in 1970, and impounds the Pohick Creek in Burke, huntsman Lake was built in 1973, and impounds the Middle Run in Springfield. Lake Royal was completed in 1977, and impounds the Rabbit Branch in Burke above its confluence with the Sideburn Branch, Lake Barton completed in 1978, impounds a tributary of the Sideburn Branch in Burke. Woodglen Lake, which impounds the Sideburn Branch in Fairfax, was completed in 1981, Lake Mercer became in 1985 the final dam completed, impounding the South Run in Springfield. The following variant names have been listed on the Geographic Names Information System by the United States Geological Survey

43.
Occoquan River
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The Occoquan River is a tributary of the Potomac River in Northern Virginia, where it serves as part of the boundary between Fairfax and Prince William counties. The river is 24.7 miles long, and its watershed covers about 590 square miles and it reaches the Potomac at Belmont Bay. The Occoquan River is part of the Chesapeake Bay watershed, the name Occoquan is derived from a Doeg Algonquian word translated as at the end of the water. The river is an area, and many local high schools. Between c.1900 and 1976, it was frequently called Occoquan Creek, the Occoquan has three dams along its length. The first is at the town of Occoquan, a reservoir belonging to the Fairfax County Water Authority, the Occoquan Reservoir stretches from Occoquan to Bull Run. The dam that creates Lake Jackson is at Virginia State Route 234, Dumfries Road, today the dam contains the lake, but has not produced electricity in several decades. There is a dam up Broad Run from its confluence with Cedar Run, this dam forms Lake Manassas. Sandy Run Regional Park is at Fairfax Station and consists of the arm of the Occoquan Reservoir. The park is used exclusively for the education, practice, the high schools who use this park for rowing are members of the Virginia Scholastic Rowing Association. Stuart High School, and South County Secondary School, Fountainhead Regional Park is also in Fairfax Station, further upriver from Sandy Run Regional Park, past Bull Run. Lake Braddock Secondary School, Westfield High School and Woodbridge High School, also VASRA members, the Occoquan River is bordered by three parks administered by the Northern Virginia Regional Park Authority. The three parks are Bull Run, Occoquan, and Fountainhead, in addition to horse riding, trailing cycling, fishing and boating access, the Bull Run to Occoquan trail travels through all three parks from the beginning of the river to its end. The Oxford Boathouse also exists here, hosting Hylton High School, Potomac High School, Gar-Field High School, and Forest Park High School

Occoquan River
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Occoquan River near Fountainhead Regional Park

44.
Mattawoman Creek
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Mattawoman Creek is a 30. 0-mile-long coastal-plain tributary to the tidal Potomac River with a mouth at Indian Head, Maryland,20 miles downstream of Washington, D. C. It comprises a 23-mile river flowing through Prince Georges and Charles counties, about three-fourths of its 94-square-mile watershed lies in Charles County, with the remainder in Prince Georges County immediately to the north. John Smiths circa-1608 map as Mataughquamend, an Algonquian compound translated as one goes pleasantly. ”Today, Mattawoman Creek is listed by the Environmental Protection Agency as impaired under Section 303 of the Clean Water Act for excess nutrients, sediment. Especially abundant are anadromous alewife, blueback herring and American shad and semi-anadromous white and yellow perch. The largemouth bass, a resident gamefish that supports an active recreational fishery in the tidal freshwater Potomac River and its tributaries, also high concentrations in the estuary. ”The estuary supports extensive freshwater tidal marshes that are partially protected as Maryland Wildlands. Mattawoman drains the town of Indian Head, the town of Bryans Road, and most of Waldorf and its watershed remains over 50% forested but is approaching a 10% impervious cover, often cited as a threshold for significant degradation as measured by water quality and species diversity. C. The ecological integrity of the Mattawoman is at risk from current, proposals for two four-lane highways that would cross the fluvial stream, and the expected attendant development, have generated debate. The first, the Western Waldorf Bypass, is one of three alternatives being considered by state and federal agencies for the U. S.301 Waldorf-Area Transportation Improvements Project and this highway would divide lengthwise about one-half of the Mattawoman watershed. The second, for which controversial wetlands permit applications have been submitted, is a extension of Charles County’s Cross County Connector. According to the Geographic Names Information System, Mattawoman Creek has also known by the following names

Mattawoman Creek
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Freshwater-tidal estuary of Mattawoman Creek

45.
Quantico Creek
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Quantico Creek is a 13. 7-mile-long tidal tributary of the Potomac River in eastern Prince William County, Virginia. Quantico Creek rises southeast of Independent Hill, flows through Prince William Forest Park, john Smith in 1608 reported the existence of a Doeg community called Pamacocack on the banks of this creek, as well as on the directly opposite side of the Potomac. This is thought to be a candidate for the place Henry Spelman was found living among the natives, which he reported was named Nacottawtanke. Early land patents spell the name of the creek variously as Quancico, Quanticotte, Quantecot, Quanticoke, Quonticutt, in 1690, settler Richard Gibson erected a gristmill on Quantico Creek near what is now the town of Dumfries. Scottish settlers then established a settlement and port on the estuary of Quantico Creek downstream after the bars to Virginias profitable tobacco trade were lifted by the Navigation Law of 1707. West of that port, the land was cleared of its timber and was planted with crops such as cotton. These cash crops were harvested and shipped out through the port of Dumfries at the head of the Quantico harbor, a customhouse and warehouse followed in 1731, and many others cropped up along the estuary by 1732. The growth of tobacco caused the area around the creek to erode, both mines were significant sources of pollution on the creek. The pyrite mine was a source of acid, formed from the natural breakdown of pyrite. At one point, the water in the creek was nearly as acidic as vinegar, both mines have since undergone significant reclamation to restore the creek and its surroundings to an acceptable state of health, especially within the park. Today, the creek is not navigable because of silting in, most of its watershed lies in Prince William Forest Park and the town of Dumfries. The mines are no longer in operation, a power plant on Possum Point uses the water from the creek to cool itself. Several communities, some extinct, lie near Quantico Creek, communities are listed from the Quanticos source to its mouth on the Potomac. S. Geological Survey, Reston, VA20192, retrieved April 7,2006